1996 AES Annual Meeting Abstracts

Adams, D.H., Mitchell, M.E., and Parsons, G.R.
(DHA) Florida Marine Research Institute, Florida Department of Environmental Protection, 1220 Prospect Ave., Suite 285, Melbourne, FL 32901 USA; (MEM) Florida Marine Research Institute, Florida Department of Environmental Protection, 1481-A Market Circle, Port Charlotte, FL 33953 USA; (GRP) Department of Biology, University of Mississippi, University, MS 38677 USA

Seasonal occurrence of the white shark, Carcharodon carcharias, in waters off the Florida west coast

The white shark, Carcharodon carcharias, is considered rare in the Gulf of Mexico, however recent longline captures coupled with historical landings information suggest that the species occurs seasonally (winter-spring) within this region. We examined a total of seven adult and juvenile white sharks (185- 472 cm total length) captured in waters off the west coast of Florida. Commercial longline fisheries were monitored for white sharks during all months (1981-1994), but this species was captured only from January to April. All white sharks were captured in continental shelf waters from 37 to 222 km off the west coast of Florida when sea surface temperatures ranged from 18.7ø to 21.6øC. Depths at capture locations ranged from 20 to 164 m. Fishing gear typically used in Gulf of Mexico offshore fisheries may not be effective at capturing this species and the apparent rarity of white sharks in this area may be, in part, a function of gear bias. (Poster Session 2, Sunday June 16, Vieux Carre B, 06.) KEYWORDS: CARCHARODON CARCHARIAS, WHITE SHARK, FLORIDA, DISTRIBUTION

Amesbury, E., and Snelson, F.F.
Department of Biology, UCF, Orlando, FL 32816-2368 USA

Embryonic development in the stingray Dasyatis sabina

Embryonic development of the stingray, Dasyatis sabina, was studied in a population from the east coast of Florida. Eggs were ovulated by mid-April. An embryonic streak was visible in late May in encapsulated uterine eggs. External gill filaments persisted in the earliest stages of gestation and were resorbed when embryos reached about 850 mg (dry weight). Early embryos received nourishment from the external yolk. Yolk passes directly into the antero-dorsal end of the spiral valve via a vitelline duct. The external yolk stalk and gill filaments will be histologically described. During mid-gestation only vestiges of a yolk sac remained, and embryos were entirely dependent on histotroph nutrition. Comparison of weights of fertilized eggs with mid-term embryos revealed a 16 fold increase. Mean embryo weight was about 4200 mg. In late- gestation, mean embryo weights and disk widths were about 7000 mg and 95 mm, respectively. Late-term embryo weights were 26 times those of fertilized eggs. Contents were stored in the spiral valve throughout development. Embryo liver weight increased linearly with embryo body weight throughout gestation. Parturition occurred from late July into mid-August. (Session 24, Sunday June 16, Cabildo, 11:00) KEYWORDS: DASYATIS SABINA, EMBRYONIC DEVELOPMENT, EXTERNAL YOLK SAC, EXTERNAL GILL FILAMENTS, SPIRAL VALVE

Bailey, C.M., Mace, P.M., McLaughlin, S.A., and Schulze, M.B.National Marine Fisheries Service

Federal management of Atlantic shark resources

The National Marine Fisheries Service (NMFS) implemented the Atlantic Sharks FMP in April 1993. After the FMP was put in place, the responsibility for the day- to-day management of the shark fisheries was given to the Highly Migratory Species Management Division (HMS Division) of the Office of Fisheries Conservation and Management in NMFS. The lack of good landings data for sharks (particularly species-specific data) and the controversial practice of “finning” were critical issues in the push for implementation of the FMP. In addition to a prohibition on finning, the FMP regulates the level of harvest through commercial quotas and recreational bag limits. The Federal management program seeks to prevent overfishing of shark resources, to encourage management of stocks throughout their ranges, and to establish effective data collection, research, and monitoring programs. The FMP manages 39 species, divided into 3 groups – large coastals, small coastals, and pelagics. The large coastals (22 species) are considered overutilized while the small coastals (7 species) and pelagics (10 species) are considered fully utilized. Accurate species identification continues to be a problem. The HMS Division and the Northeast and Southeast Fishery Science Centers of NMFS have initiated a program called the Integrated Shark Research and Management Program, or ISHARK, in order to accomplish a variety of tasks, the first being to produce a valid index of nursery/pupping areas. ISHARK also seeks to coordinate various scientific aspects of NMFS in a concerted effort to answer specific management related questions about sharks. NMFS hopes to work with other countries to establish a multilateral management and monitoring system (with the United States, Canada, Mexico, and Caribbean Basin countries as a start). NMFS is committed to an interactive, integrated research and management program for Atlantic sharks that involves researchers, managers, and fishery interests in a team effort to effectively manage these species. (Session 11, Saturday June 15, Cabildo, 10:15) KEYWORDS: SHARKS, MANAGEMENT, FEDERAL, INTEGRATED, HIGHLY MIGRATORY SPECIES

Benz, G.W., and Kohl, J.W.
(GWB, JWK) Tennessee Aquarium, P.O. Box 11048, Chattanooga, TN 37401-2048 USA

Ecological analysis of parasitic copepods living up the nose of blue sharks

The distribution of 1623 Kroeyerina elongata (Copepoda: Siphonostomatoida) collected from the left olfactory sacs of 14 blue sharks (Prionace glauca) was analyzed. Numbers ofK. elongata per olfactory sac ranged from 0-228. Female copepods typically outnumbered males (mean number of males per female = 0.487). Both males (96.8 percent) and females (99.0 percent) appeared positively reotactic with respect to water flow through the olfactory sac, and adults of each sex seemed to prefer different locations within the olfactory sac. Ovigerous females typically attached at the base of the rachis or within the first third of the excurrent water channel, while males tended to attach randomly about the secondary lamellae of the olfactory sac. It is interesting that the few subadult females that were collected (some of them paired with males) were distributed in male-like fashion. When these results are interpreted in light of the pattern of water flow throughout the olfactoary sac they suggest some mechanisms via which the nose is initially colonized and the realized niche of these parasites is ultimately achieved. (Session 18, Saturday June 15, Cabildo, 02:45) KEYWORDS: BLUE SHARK, PRIONACE GLAUCA,KROEYERINA ELONGATA, PARASITE, PARASITIC COPEPODS, OLFACTORY SAC, SPATIAL DISTRIBUTION

Bodine, A.B., Castro, J.I., Wyffels, J.T., Shafer, G.J., and Rodgers, R.S.
(ABB, JTW, RSR) Animal, Dairy and Veterinary Sciences Department, Clemson University, Clemson, SC 29634 USA; (GJS) Chemistry Department, Clemson University, Clemson, SC 29634 USA; (JIC) NOAH/NMFS, SEFC, 75 Virginia Beach Dr., Miami, FL 33149 USA

Isolation, and characterization of carotenoid pigments from the Golden hammerhead, Sphyrna tudes

Studies were conducted to extract and characterize the pigment(s) from the skin of the Golden Hammerhead, Sphyrna tudes. Juvenile specimens of this species were obtained from the waters near Trinidad and stored frozen until subsequent preparation and analysis of skin extracts. Fin and skin sections were extracted with chloroform/methanol ( 9:1 v/v ) containing 0.05% butylated hydroxy toluene as antioxidant in an explosion-proof blender for 5 minutes at high speed. The yellow-orange extract was filtered through glass fiber filters and concentrated by flash evaporation. Extract components were resolved by 2000u thick-layer chromatography using chloroform/methanol ( 97:3 v/v ) as mobile phase. Dark yellow to yellowish- orange bands were located at Rf 0.75-0.80. These fractions were removed by a vacuum fraction cutter and the pigments extracted from the silica gel with chloroform/methanol ( 97:3 v/v ). The pigment solutions were analyzed by reversed phase HPLC using alpha-carotene, beta-carotene, and xanthophyll as internal and external standards. Pigments from the skin and fins were shown by HPLC, Fourier transform infrared, proton and carbon-13 nuclear magnetic resonance, and mass spectroscopy to be > 98% alpha and beta carotenes and a very minor amount of presumably oxidation product(s). No xanthophyll was detected in the skin extracts. (Session 18, Saturday June 15, Cabildo, 01:30) KEYWORDS: GOLDEN HAMMERHEAD, CAROTENOIDS, CAROTENOPROTEIN, HPLC

Bonfil, R.
Fisheries Center, University of British Columbia, 2204 Main Mall, Vancouver, BC V6T 1Z4 Canada

Can simple fishery models be used for elasmobranch stock assessment?: a Monte Carlo simulation approach

The identification of adequate assessment methods for shark and ray fisheries is of prime importance for their sustainable management and conservation. This study aims at: i) determining the accuracy of the Schaefer, Fox, and Deriso fishery models, for the estimation of assessment and management parameters of elasmobranch stocks; ii) which model is best, and iii) how robust these models are. The fishery models are tested via Monte Carlo simulation within the context of the operating model concept, using stochastic simulation models of a fully age-structured shark population and a harvesting system. Ten different scenarios are analysed to test the robustness of the fishery models, including variations in the stock recruitment relationship, age of entry to the fishery, spatial behaviour of the sharks, and quality of the fishery data. None of these three fishery models performs satisfactorily under situations of density-dependent catchability. Under constant catchability, the Deriso model outperforms the Schaefer or Fox models, both for biomass and management parameter estimation. Surplus production models are not recommended for the estimation of management parameters in elasmobranch fisheries, but could be used for biomass assessment. Data quality plays a very important role in the performance of all models for parameter estimation. (Session 04, Friday June 14, Cabildo, 03:45) AES – Samuel Gruber Award KEYWORDS: SIMULATION MODELS, FISHERY MODELS, ELASMOBRANCH ASSESSMENT

Bradley, J.L., IV, and Tricas, T.C.
(JLB and TCT) Department of Biological Sciences, Florida Tech, Melbourne, FL 32901-6988, USA

Prey selection, habitat use, and daily ration of the Atlantic stingray, Dasyatis sabina

Batoid elasmobranchs are important benthic carnivores, but their trophic dynamics are largely unknown. The Atlantic stingray, Dasyatis sabina, is a common benthic carnivore on small invertebrate prey in estuarine habitats. Amphipods and bivalves were more abundant in the diet, while polychaetes occurred less frequently in the diet than expected from their distribution in the habitat. Isopods, mysids, and ophiuroids were taken as expected. More feeding pits occurred within sand (81%) than in the sand-seagrass interface (15%) or seagrass (4%) subhabitats. Stingrays fed more frequently within sand (29%) and interface (30%) than in seagrass (8%) subhabitats. Lack of variation in digestive states of prey and caloric density of stomach contents over time indicate stingrays fed continuously through the diel cycle. Daily ration was estimated in July (27 – 33 °C) at 2.52 %BW/d and is equivalent to the consumption of 15,000 amphipods/d or 48 kcal/d. Prey abundance in the diet may be directly proportional to prey abundance in the habitat although seasonal changes in ophiuroids are associated with changes in caloric content. Energy consumption by rays in summer is estimated as high as 45 million cal/km{+2/d and may directly impact the diversity of invertebrate communities. (Session 04, Friday June 14, Cabildo, 03:15) AES – Samuel Gruber Award KEYWORDS: DAILY RATION, DASYATIS SABINA, FEEDING ECOLOGY, HABITAT USE, PREY SELECTION, TROPHIC DYNAMICS

Branstetter, S., and Burgess, G.H.
(SB) Gulf and South Atlantic Fisheries Development Foundation, Ste. 997, 5401 W. Kennedy, Tampa, FL 33609, USA; (GHB) Florida Museum of Natural History, University of Florida, Gainesville, FL 32611 USA

Characterization and status of the southeast U.S. commercial shark fishery with recommendations for sustainability

During 1994-95, three at-sea observers monitored shark fishing operations, documenting 2.3% of the federal quota for the period. Blacktip Carcharhinus limbatusand sandbar C. plumbeus sharks constituted 66% of the large-coastal catch and >80% of the large-coastal landings for the areas surveyed. For the entire U.S east coast, sandbar (47%) and blacktip (25%) sharks may represent 72% of the total large-coastal landings. No consistent trends occurred in catch rates for any strata we examined. Slightly more than 50% of the sandbar and blacktip sharks were mature. For sandbar sharks, females constituted 74% of the North Carolina area catch, 43% in the southeast Atlantic region, and 55% in the eastern Gulf of Mexico. About 25% of the North Carolina blacktip shark catch was female, whereas for Florida, 55% was female. Current demographic information suggests the sandbar shark stock is being overfished. With more measured fishing efforts, modified fishing tactics, and an updated management strategy this stock should show recovery. Similar demographic information is not available for the blacktip shark or other common large coastal species. The blacktip shark may not be negatively impacted because of its lesser contribution to the fishery and greater resiliency in life history traits. (Session 11, Saturday June 15, Cabildo, 09:45) KEYWORDS: SHARKS, FISHERY,CARCHARHINUS PLUMBEUSCARCHARHINUS LIMBATUS, DEMOGRAPHICS

Bratton, B.O.
Neuroscience Program, Oberlin College, Oberlin, OH 44074 USA

Electric organ discharge of the skate (Rajidae): occurrence and behaviour relationships

Members of the elasmobranch family Rajidae, commonly known as skates, possess weak electric organs that are intermittently active with low and variable amplitudes. The electric organ discharge (EOD), recorded from isolated individuals and small groups during spawning and non-spawning interactions have shown differences in pulse duration, patterns, frequency, and train length, that are species and behavior specific. Isolated skates rarely discharge while groups of skates are found to discharge regularly. During approach and contact, skates respond to each other with interacting EOD displays that consist of pulse trains ranging from 1 to 90 EODs R. ocellata. Pulse trains range from 1.0 to 7.5 pps and are consistently produced when in contact with other skates. Rapid pulse rates (7.5 pps) occurred most often during aggressive interactions between conspecifics and occasionally continuous pulse rates of 0.4 to 0.6 pps were observed during isolation (R. ocellata). Waveform characteristics in shape, polarity, number of phases, amplitude and waveform frequency in seven species (Raja erinaceaR. ocellataR. clavataR. montaguiR. microocellataR. radiata and R. eglanteria) displayed a species specific EOD pulse duration (31 to 217 ms). Behavioral (EOD) interaction and pulse duration differences between species suggest a possible communication function. (Session 44, Monday June 17, Cabildo, 01:45) KEYWORDS: SKATE, ELECTRIC ORGAN DISCHARGE, RAJASP., ELECTROCOMMUNICATION

Brown-Peterson, N.J., Hawkins, W.E., and Overstreet, R.M.
Gulf Coast Research Laboratory, 703 E. Beach Rd, Ocean Springs, MS 39564 USA

Assessment of histopathological biomarkers in blacktip shark, Carcharinus limbatus, from the Gulf of Mexico

Sharks are wide-ranging species and usually the apex predator within their ecosystem. Thus, sharks appear to be a good choice as biological indicators of environmental health. We examined tissues from major organs of 17 blacktip sharks from Charlotte Harbor, FL, and Mississippi Sound, MS, to assess cellular biomarkers. Tissues were fixed in 10% NBF and processed for histological examination. Slides were stained routinely with H&E and immunohistochemically for proliferating cell nuclear antigen (PCNA). Histological observations included macrophages in liver tissue (95% of samples), thickening of secondary lamellae in gill (90%), tubular debris in kidney (41%) and pancreas (33%) and lymphocytic infiltration in spleen (97%). Additionally, parasitic cysts were found in gill (40%), heart (19%), liver (8%), spleen (8%) and pancreas (9%). No granulomas were observed and macrophage aggregate incidence in spleen tissue was low (6%). PCNA staining showed developing nephrons (44%) and proliferating cells in thickened areas of gill secondary lamellae (80%) and in kidney tubules (84%). The proliferation did not appear to be related to tissue injury. These preliminary results suggest that shark tissues are amenable to histologic and immuncytochemical biomarker analysis but the value of these markers as indicators of environmental health remains to be determined. (Poster Session 2, Sunday June 16, Vieux Carre B, 10.) KEYWORDS: HISTOLOGY, CARCHARINUS LIMBATUS, BIOMARKERS, IMMUNOHISTOCHEMISTRY, CELL PROLIFERATION

Bruner, J.C.
Department of Biological Sciences, and Laboratory for Vertebrate Paleontology, University of Alberta, Edmonton, Alberta T6G 2E9 Canada

Antisymmetry in number of tooth positions indicates high stress within an Eastern Pacific population of Squalus acanthias Linnaeus, 1758

Analysis of 34 specimens (TL 67 to 92.6 cm) of Squalus acanthias from Baja California, Mexico finds antisymmetry within the number of tooth positions in both the upper and lower jaws. Although the distribution of left – right rows for the upper jaws is fairly symmetrical about zero, the lower jaws demonstrate a higher fluctuating asymmetry (FA) with 23/34 specimens having higher number of tooth rows on the right side of the lower jaw. Since a high FA indicates a high level of stress in the population, it is hypothesized that this population of spiny dogfish is under stress. Surprisingly, the dental formulae for this Pacific population was found to be intermediate to reported tooth formulae for the same species in the western North Atlantic and the eastern South Atlantic. Teeth in the upper jaw: 12 to 15 – 0 (or 1) – 13 to 15. Teeth in the lower jaw: 11 to 13 – 0 – 11 or 12. Also, since a functional series of teeth are reported as being replaced at once, it is hypothesized that the Z – spacing of the Zahnreihen (or, tooth rows) ranges from 11 to 15 as opposed to the more primitive alternate replacement of functional teeth (Z – spacing of 2). (Session 04, Friday June 14, Cabildo, 02:30) AES – Samuel Gruber Award KEYWORDS: SQUALUS ACANTHIAS, BAJA CALIFORNIA, ANTISYMMETRY, FLUCTUATING ASYMMETRY, Z – SPACING, ZAHNREIHEN

Callahan, M., Burgess, G.H., and Branstetter, S.
(MC,GHB) Florida Museum of Natural History, University of Florida, Gainesville, FL 32611 USA; (SB) Gulf and South Atlantic Fisheries Development Foundation, Ste. 997, 5401 W. Kennedy, Tampa, FL 33609 USA

The Gulf of Mexico commercial shark fishery off Florida, 1994-5

In 1994-5 the directed shark fishery in the eastern Gulf of Mexico off Florida’s west coast was monitored by an at-sea observer on 23 fishing trips. This area produced roughly 25% of the U.S. Atlantic catch in 1994-5; we documented at least 2.0% of this region’s catch during each season. Longline sets typically utilized 11.3 miles of longline and 950 hooks. One hundred observed sets captured over 2,250 sharks, resulting in a CPUE of 17.2 sharks per 10,000 hook/ hr. Large coastal (LC) species, which had a CPUE of 15.5 sharks per 10,000 hook- hr, represented more than 90% of the total catch. By number, sandbar (Carcharhinus plumbeus) and blackip (C. limbatus) sharks comprised 39% and 21% of the LC catch, with CPUEs of 6.1 and 3.8 sharks per 10,000 hook-hr, respectively. The blacknose shark (C. acronotus) comprised 84% of the small coastal (SC) species catch. Sandbar (55%) and blacktip (27%) sharks contributed 82% of the LC landings by number. Sex ratios favored female (52%) blacktip and male (55%) sandbar sharks. Analysis of length frequency data reveals that 59% of sandbars caught were mature, while only 24% of blacktips caught were mature. (Session 11, Saturday June 15, Cabildo, 09:15) KEYWORDS: SHARK, FISHERY, CARCHARHINUS ACRONOTUS,CARCHARHINUS PLUMBEUSCARCHARHINUS LIMBATUS, FLORIDA

Campbell, R.A.
Department of Biology, UMASS Dartmouth, N. Dartmouth, MA 02747-2300 USA

The protozoan and metazoan parasites of skates

Skates harbour less diverse parasite faunas than rays but share representatives of related taxa. The parasite assortment includes ectoparasites that feed upon body surfaces and invade orifices, or endoparasites inhabiting the blood, tissues, internal organs and body cavity. A complete faunal survey of skate parasites includes four protozoan phyla and metazoans of the cnidaria, four platyhelminth classes, nematoda, acanthocephala, hirudinea and several groups of parasitic crustacea. The families and genera of parasites often have circum-boreal and bipolar distributions. Monogenea and cestodes of several families show a co-evolutionary specificity for batoids. Four orders of tapeworms show microhabitat distributional preferences within the spiral intestine of their hosts. The helminth fauna of the skate species may mirror changes in fish diet with age, fish migrations, depth of capture and geographical locality. Highest diversity and distribution of some parasite taxa corresponds to specific latitudes or depth of host habitat. Parasite species may be used to advantage to study aspects of host biology and to support fish systematic works. (Session 38, Monday June 17, Cabildo, 09:00) KEYWORDS: PARASITES, PROTOZOA, WORMS, CRUSTACEA, BIOLOGICAL TAGS, RAJIDAE

Carlson, J.K., and Parsons, G.R.
(JKC) NMFS, Panama City, FL 32408; (GRP, JKC) Biology, University of Mississippi, University, MS 38677 USA

Swimming and respiratory responses of the bonnethead shark, Sphyrna tiburo, to hypoxia

Swimming speed, respiration rate, and mouth gape responses to reductions in ambient oxygen were measured in the bonnethead shark, Sphyrna tiburo, a ram ventilating species. In a static respirometer under normoxic conditions, sharks swam at 20-25 cm/sec. However, a significant increase in swimming speed was observed when oxygen levels reached about 5.0 ppm and a maximum speed of about 38 cm/sec was observed at 3.5 to 4.0 ppm dissolved oxygen. Concurrently, mouth gape and respiration rate was found to increase with decreasing oxygen levels. Gape was constant at about 1 cm under normoxic conditions but increased to 3.5 to 4.5 cm during hypoxia. Respiration rate was around 175 mg oxygen/hr at 6.0 ppm but increased to about 500 mg oxygen/hr at 3.5 ppm. This was not unexpected given the rise in swimming speed observed. We also observed that increasing levels of oxygen in the respirometer resulted in decreases in swimming speed, respiration rate, and mouth gape. The response of the bonnethead shark to decreasing oxygen suggest that ram ventilating sharks employ an increase in swimming speed and mouth gape as a means for regulating ventilation volume and maintaining blood oxygen levels. (Session 04, Friday June 14, Cabildo, 04:00) AES – Samuel Gruber Award KEYWORDS: SWIMMING SPEED, HYPOXIA, GAPE, RESPIRATION RATE, BONNETHEAD SHARK

Carrier, J.C., and Pratt, H.L., Jr.
(J.C.C.) Department of Biology, Albion College, Albion, MI 49224 USA; (H.L.P., JR.) NOAA/NMFS, Narragansett Lab, 28 Tarzwell Drive, Narragansett, RI 02882 USA

Identification and closure of a nurse shark breeding grounds

Ongoing studies of nurse shark mating have identified a population that undergoes mating and parturition in one specific site in the Florida Keys. Our tagging, observation, and filming have demonstrated that reproductive activities occur preferentially for some animals in very shallow coastal waters, and one such site has been studied intensely for the last five years. From our investigations we have learned that mating activities of the sharks in this area are vulnerable to the disruptive effects of wading, diving, photography (electronic flash), boat traffic, and human presence during the times when mating occurs. To reduce disruptive activities during the mating season, a proposal to protect this mating and nursery grounds was submitted to the National Park Service and the Florida Keys National Marine Sanctuary Program. Three elements of protection which we felt were critical to implement were to: 1) recognize the specific area as unique and critical to the breeding success of the sharks, 2) restrict the public during times identified by our research as essential for mating, and 3) implement a program of public education. A description of the designation process and details of the area closure will be presented. (Session 46, Monday June 17, Vieux Carre A, 03:15) KEYWORDS: REPRODUCTION, NURSE SHARK, MATING, REPRODUCTION, BEHAVIOR, CLOSURE, SANCTUARY, BREEDING

Carvalho, M.R.de, Maisey, J.G., and Grande, L.
(MRC) Department of Ichthyology, AMNH, Central Park West at 79th St., New York, NY, 10024 and Graduate School, The City University of New York, New York, NY, 10036 USA; (JGM) Department of Vertebrate Paleontology, AMNH, Central Park West at 79th St., New York, NY, 10024 USA; (LG) Department of Geology, Field Museum of Natural History, Roosevelt Road at Lake Shore Dr., Cicago, IL, 60605 USA

Freshwater stingrays of the Green River Formation (late early Eocene) of Wyoming, with the description of a new genus and species (Chondrichthyes, Myliobatiformes)

The late early Eocene Green River Formation (Fossil Butte Member) of Wyoming has yielded, among numerous taxa of bony fishes, two distinct forms of stingrays. One of these,Heliobatis radians Marsh, 1877 has been heavily sampled and is present in many private and public collections. This taxon resembles Recent dasyatidids in many respects, and is known primarily from adult and sub-adult specimens of both sexes. The other stingray form is presently being described and is known from fewer specimens, both juvenile and adult of both sexes. The new genus is diagnosed on the basis of a combination of characters, including the presence of a dorsal fin anterior to the caudal stings, heavy denticulation on the dorsal surface of disc and dorsal fin, and stout tail at base. The anatomy of these taxa is described and comparisons with Recent stingray genera are conducted, along with a discussion of their phylogenetic relationships. (Session 24, Sunday June 16, Cabildo, 09:45) KEYWORDS: GREEN RIVER FORMATION, FRESHWATER STINGRAYS,HELIOBATIS RADIANS, NEW GENUS AND SPECIES, ANATOMY, PHYLOGENY, MYLIOBATIFORMES

Castillo-Geniz, L., and Marquez-Farias, F.
Programa Tibur<o>n, Instituto Nacional de la Pesca, Pit<a>goras #1320, 4{+o Piso, Col. Santa Cruz Atoyac, C.P. 03310, Distrito Federal, México

Shark nursery areas in Mexican waters of the Gulf of Mexico: the case of Matamoros, Tamaulipas

An intensive monitoring of the artisanal coastal shark fisheries from Mexican waters of the Gulf of Mexico was carried out from November 1993 to December 1994. Biological and fishery data on the main shark species allowed us to determine important shark nursery areas in the region. In Matamoros, Tamaulipas, which is located near the U.S. border, a total of 10,737 sharks corresponding to 17 species were recorded from April to November 1994. At this locality, a large number of gravid female and neonate Atlantic sharpnose sharks, Rhizoprionodon terraenovae, and blacktip sharks, Carcharhinus limbatus, were landed during April-May. Neonates and juveniles of other carcharhinid species also were present in the artisanal catches during the same period. Most of the catches came from shallow waters in the area, indicating that this specific part of the continental shelf constitutes a non-protected nursery area for several carcharhinid species. Fishery management measures leading to a reduction in fishing mortality in these shark nursery areas will be an important component of the conservation and management of the main shark stocks that support this important fishery for Mexico. (Session 24, Sunday June 16, Cabildo, 09:15) KEYWORDS: MATAMOROS, MEXICO, ARTISANAL FISHERY, SHARK NURSERY AREAS, REPRODUCTION, ATLANTIC SHARPNOSE SHARK, RHIZOPRIONODON TERRAENOVAE

Castro, J.I., Clark, E., Yano, K., and Nakaya, K.
(JIC) National Marine Fisheries Service/NOAA, Southeast Fisheries Science Center, 75 Virginia Beach Drive, Miami, Florida 33149, USA; (EC) Department of Zoology, University of Maryland, College Park, Maryland 20742, USA; (KY) Seikai National Fisheries Research Institute, Ishigaki Tropical Station, Fisheries Agency of Japan, 148 Fukai Oota, Ishigaki, Okinawa 907-04, Japan; (KN) Laboratory of Marine Zoology, Faculty of Fisheries, Hokkaido University, 3-1-1, Minato-cho, Hakodate, Hokkaido 041, Japan.

The gross anatomy of the female reproductive tract of the Fukuoka megamouth shark (Megachasma pelagios)

A 4.71 m TL, 800 kg megamouth shark (Megachasma pelagios) was stranded in a shallow cove on the NE coast of Hakata Bay, Fukuoka, Kyushu, Japan, on 29 November 1994. This is the first female specimen of the megamouth shark examined by scientists. The oviducts from ostium to cloaca and a single ovary were removed from the specimen. The ovary is in the right side of the anterior body cavity. It is of the lamnoid type and has innumerable oocytes in the same stage of development, and a single funnel-fold on its ventral surface. Oocytes measured 1.1-2.3 mm in diameter. The ostium was poorly differentiated. The oviducts anterior to the shell gland are thin and narrow, about 5 mm in diameter. The shell glands were also poorly developed. The uteri are not fused together at their posterior ends but open into separate vaginas which are covered by a thick hymen. The small size of the oocytes, the thin oviducts and uteri, and the poorly developed ostium, all indicate that the specimen was immature. The type of ovary suggests that megamouth is oophagous. (Session 24, Sunday June 16, Cabildo, 10:45) KEYWORDS: MEGAMOUTH, MEGACHASMA PELAGIOS, FUKUOKA, REPRODUCTION

Childs, J.
Wildlife & Fisheries Sciences Dept., TAMU, College Station, TX 77843-2258 USA

Activity patterns of mobulid rays with three topographic highs in the northwest Gulf of Mexico

Recent observations in the northwest Gulf of Mexico suggest manta rays (Manta birostris) and other pelagic elasmobranchs, may associate with topographic highs. Topographic highs are defined as natural or artificial elevations rising up from the sea floor that provide significant vertical and structural relief in an otherwise homogeneous landscape. In situ observations of pelagic elasmobranchs conducted at the East and West Flower Garden and Stetson Banks, reveal the occurrence of three species of mobulid rays (Manta birostris,Mobula hypostoma, and M. tarapacana). The occurrence of (Mobula tarapacana) is a new record for this region of the North Atlantic Ocean. Individual rays were identified using photographic image analysis. Patterns of movement and migration, spatial and temporal resource use, social organization and interactions were examined to reveal important charactersitics regarding the ecology and behavior of mobulids rays in relation to the topographic highs sampled. (Session 04, Friday June 14, Cabildo, 02:00) AES – Samuel Gruber Award KEYWORDS: MOBULID RAYS, PELAGIC FISHES, TOPOGRAPHIC HIGHS, GULF OF MEXICO, MOBULIDAE, MANTA BIROSTRIS,MOBULA SPP

Correia, J., Figueiredo, I., and Figueiredo, M.J.
(JC, IF, MJF) D.R.M., Inst. Port. Invest. Mar<i>tima, Av. Bras<i>lia, 1400, Lisboa, Portugal

Preliminary results on age and growth from blackmouthed catsharks from Portuguese waters

During a survey held on board the IPIMAR R/V “Noruega” in August 1994, 477 vertebral centra were removed from Blackmouthed Catsharks, Galeus melastomus. The centra were prepared and observed following a protocol established earlier by the same authors. Bands were counted and measured and these data were used to construct growth curves based on Schnute’s versatile growth model. Growth parameters for both females and males were estimated using the Simplex method. Our results show that females have a growth pattern similar to patterns already established for other elasmobranch species, reaching an asymptotic length at aprox. age 14. Males, on the other hand, do not have an asymptotic maximum length, which is most likely a result from a low incidence of adult individuals in our sample. (Session 04, Friday June 14, Cabildo, 04:15) AES – Samuel Gruber Award


Correia, J., Marignac, J., and Gruber, S.
(JC) D.R.M., Inst. Port. Invest. Mar<i>tima, Av. Bras<i>lia, 1400 Lisboa,Portugal; (JM) Bimini Biological Field Station, Bimini Islands, Bahamas; (SG) R.S.M.A.S., U. Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, USA

Young lemon shark behaviour in Bimini Lagoon

During the Winter of 1994, in Bimini Lagoon, Bahamas, four lemon sharks, Negaprion brevirostris, were tagged with ultrasonic transmitters, with total lengths ranging from 1.51 to 2.20m. The sharks were tracked for a total of 47 days and yielded 1659 geographic fixes. Movement analysis enabled us to prove that the sharks stay near Alice Town (west side of the lagoon) at night, travel east with sunrise, stay on the east side during the day and travel back west at sunset. Current observations, as well as from other authors’ experiences, allowed us to suggest that the nocturnal presence of the sharks near Alice Town is most likely to be related with foraging whereas their daily presence on the eastern side is probably associated with refuging. (Session 04, Friday June 14, Cabildo, 04:45) AES – Samuel Gruber Award KEYWORDS: LEMON SHARK, NEGAPRION BREVIROSTRIS, BIMINI LAGOON, BEHAVIORAL ECOLOGY, MOVEMENT PATTERNS, ULTRASONIC TELEMETRY

Correia, J., Marignac, J., and Gruber, S.
(JC) D.R.M., Inst. Port. Invest. Mar<i>tima, Av. Bras<i>lia, 1400 Lisboa, Portugal; (JM) Bimini Biological Field Station, Bimini Islands, Bahamas; (SG) R.S.M.A.S., U. Miami, 4600 Rickenbacker Causeway, Miami, FL 33149 USA

Rates of movement from subadult lemon sharks in Bimini Lagoon: the optimal time interval between successive fixes with notes on hand-held GPS units error estimation

Between the winter of 1994 and the summer of 1995 seventeen subadult lemon sharks,Negaprion brevirostris, have been tracked in Bimini Lagoon, Bahamas. The geographic position of the sharks has been recorded at varying time intervals and the rate of movement between successive positions (N=10004) has been calculated using a straight distance between them. Rates of movement calculated with five minute intervals (n=2611) were tested against rates of movement calculated with fifteen minute intervals (n=3704). Five minute fixes yielded higher rates of movement (1.98Km/hr) than fifteen minute fixes (1.63Km/hr) thus enabling us to conclude that five minutes is a more accurate interval than fifteen. The GPS error has been calculated in order to assess if there was an overlap of errors between successive five minute fixes. This analysis showed that there was no overlap of errors. (Session 04, Friday June 14, Cabildo, 01:30) AES – Samuel Gruber Award KEYWORDS: LEMON SHARK, NEGAPRION BREVIROSTRIS, BIMINI LAGOON, RATE OF MOVEMENT, GPS ERROR

Cortés, E.
Center for Shark Research, Mote Marine Laboratory, 1600 Thompson Parkway, Sarasota, FL 34236 USA

An algorithm for calculating diet composition of sharks

An algorithm was derived to calculate the diet composition of shark species in an attempt to consolidate quantitative studies and facilitate species comparisons. The index presented is a weighted average that allows incorporation of data from multiple quantitative dietary studies of a particular species and takes into account both the index used to quantify stomach contents and the sample size in each study. Qualitative information can also be incorporated into the index if it differs from the quantitative data. Variability in diet composition of a species due to age, season, locality, habitat, population, or other factors is thus eliminated by calculating a standardized diet composition, based on eleven food categories. Standardized diet compositions will facilitate comparison among species and be useful for calculating ecological measures in feeding ecology and trophic modelling studies. This algorithm can also be applied to other animal groups by varying the type and number of food categories considered. (Session 11, Saturday June 15, Cabildo, 10:30) KEYWORDS: DIET, STOMACH CONTENTS, SHARKS, ECOLOGICAL MEASURES

Damon, K.B.
Department of Marine Affairs, Univeristy of Rhode Island, Kingston, RI 02881 USA

Location of sandbar shark nursery and pupping grounds along the east coast of the United States

Dramatic increases in effort in both commercial and recreational shark fishing have occurred during the last decade. This increased demand for shark products has resulted in overfishing of many species of sharks. The National Marine Fisheries Service has developed and implemented a Fishery Management Plan (FMP) for Sharks of the Atlantic Ocean in order to counteract this decline. The FMP does not cover all species of sharks comprehensively due to the lack of information regarding the life histories of many species. Many shark species, including the sandbar shark Archarhinus Plumbeus, utilize estuarine systems as nursery and pupping grounds. Increased coastal development has resulted in the alteration and degradation of much of the United States coastline. The impacts on the marine organisms that utilize the coastal areas are unknown. The charting of shark nursery and pupping grounds has, therefore, been identified as a critical research need. The purpose of this presentation is to identify the locations of sandbar shark nursery and pupping grounds along the east coast of the United States and to provide insight into the environmental characteristics that this species may require in a nursery or pupping area. (Session 04, Friday June 14, Cabildo, 04:30) AES – Samuel Gruber Award KEYWORDS: SANDBAR SHARK, CARCHARHINUS PLUMBEUS, NURSERY GROUNDS, PUPPING AREAS, EAST COAST OF THE UNITED STATES

de Marignac, J.R.C., and Gruber, Samuel H
(JM) MLML, P.O. BOX 450, Moss Landing, CA 95039 USA; (SG) Bimini Biological Field Station, Bimini, Bahamas

Home range size and diel pattern of the subadult lemon shark, Negaprion brevirostris, in Bimini Lagoon, Bahamas: a progress report

Knowledge of movement patterns is important for complete understanding of the natural history and ecology of a species. The lemon shark, Negaprion brevirostris, is a common inhabitant of the shallow water of Bimini Lagoon, Bahamas. Ultrasonic transmitters were surgically implanted in 29 subadult lemon sharks (144-198 cm in total length) to study spatial and temporal movements. During November 1992 to October 1995, 11817 position fixes were recorded. Sharks were tracked continuously for periods of 24 hours whenever possible and intermittently for up to 13 months. Using a modified minimum convex polygon method, mean home range estimatesof subadults lemon sharks were an order of magnitude larger than those of juveniles (> 2 km{+2). Juveniles and subadults used only a fraction of the available habitat. Home range overlapped and aggregation of up to 25 individuals occurred, suggesting they are not territorial. Subadult lemon sharks had distinct night and day centers of activity. Lemon sharks initially captured on the western side of the lagoon at night moved eastward at dawn and westward at dusk, whereas individuals captured in the eastern side of the lagoon appeared to have a north south diel pattern. These patterns may be related to feeding or refuging. (Poster Session 3, Monday June 17, Vieux Carre B, 06.) KEYWORDS: HOME RANGE SIZE, DIEL PATTERN, LEMON SHARK, BAHAMAS

Dee, J.L., Benz, G.W., Otting, R., and Skomal, G.
(JLD) Tennessee Aquarium, P.O. Box 11048, Chattanooga, TN 37401-2048 USA and Southern College, Biology Department, P.O. Box 370, Collegedale, TN 37315 USA; (GWB) Tennessee Aquarium, P.O. Box 11048, Chattanooga, TN 37401-2048 USA; (RO) 310 Rogers Rd., Apt. S 214, Athens, GA 30605 USA; (GS) Massachusetts Division of Marine Fisheries, P.O. Box 68, Vineyard Haven, MA 02568-0068 USA

Resource partitioning of smooth dogfish by two species of parasitic copepods

The spatial distribution of two species of parasitic copepods, Pandarus sinuatus andAlebion glaber, was investigated over the external surface of smooth dogfish (Mustelus canis using data collected from 39 sharks captured off Massachusetts. Total numbers of copepods per shark ranged from 0-47, with P. sinuatus (range 0- 47) typically outnumbering A. glaber (range 0-8). Most A. glaber (75 percent males, 77 percent females) attached anterior to the origin of the first dorsal fin. Most P. sinuatus (65 percent males, 78 percent females) were collected from the second dorsal fin, and the greatest number of these (78 percent males, 81 percent females) were specifically attached at the fin s dorsal tip. Examination of placoid scales taken from various locations on several dogfish indicated that most A. glaber (97 percent) attached where scales exhibited fluted crowns, whereas most P. sinuatus (94 percent) were found where scales exhibited smooth crowns. While the primary attachment appendages of Alebion and Pandarus species are morphologically and functionally different, we found no evidence indicating that scale differences functionally restrict the distributions of these two species. Furthermore, scales similar to those found underneath each copepod species were also found at other locations where copepods were never collected. (Session 11, Saturday June 15, Cabildo, 08:00) AES – Samuel Gruber Award KEYWORDS: SMOOTH DOGFISH, MUSTELUS CANISPANDARUS SINUATUSALEBION GLABER, PARASITES, PARASITIC COPEPODS, SPATIAL DISTRIBUTION, PLACOID SCALES

Demski, L.S., Beaver, J.A., Sudberry, J.J., and Custis, J.
(LSD, JAB, JJS, JC) Division of Natural Sciences; New College of the Univ. of South Florida; 5700 N. Tamiami Trail; Sarasota, FL 34243

GnRH control of reproduction

Central to the control of reproduction in skates and other vertebrates are neuroendocrine relationships through which the neuropeptide gonadotropin hormone releasing hormone (GnRH) influences: 1) the synthesis and release of gonadotropins and thus indirectly controls gonadal steroid production and release; 2) gonadal steriodogenesis directly via local GnRH receptors; and 3) the activity in widespread neural networks including CNS sensorimotor pathways, retinal and olfactory systems. These functions are considered in a comparative context which emphasizes their potential importance in skates relative to other elasmobranchs. In skates as in other vertebrates, GnRH cells have been identified in neurons in terminal nerve ganglia, the basal forebrain, and midbrain tegmentum near the oculomotor complex. GnRH-immunoreactive fibers supply most of the CNS as well as the retina, olfactory bulbs and olfactory epithelium. In both skates and torpedo rays, GnRH has been demonstrated to trigger steroidogenesis directly via local receptors in gonadal tissue; the observations are consistent with a possible physiological role for high levels of GnRH in the general circulation. Studies in teleosts suggest that GnRH functions as a modulator of synaptic activity in widespread CNS pathways likely to control mating. (Session 44, Monday June 17, Cabildo, 03:00) KEYWORDS: SKATES, GNRH, REPRODUCTION

Deynat, P.P.
Laboratoire d’Ichtyologie générale et Appliquée, 43 rue Cuvier, 75231 Paris Cedex 05, FRANCE

Comparative morphology of dermal denticles and tubercles and their taxonomic significance in the Pristiformes and Rajiformes

Dermal armature of 149 species of Pristiformes and Rajiformes has been studied. Morphological variations in both juveniles and adults have been analyzed in order to determine their taxonomic value within the Pristiformes and Rajiformes. Among the sawfishes, the genus Pristis is divided into two major groups; the status of Anoxypristis is still questionable. Among the guitarfishes, the species Rhina ancylostoma andRhynchobatus lübberti share dermal characteristics suggesting close relationship of the Rhinidae to the Rhynchobatidae. The genera RhinobatosAptychotremaZapteryx,Zanobatus and Trygonorrhina have in common a particular superficial relief of their tubercles. ZapteryxZanobatus and Trygonorrhina are set apart from other Rhinobatidae by the covering of the basal plate of their tubercles; the status of Zapteryx exasperata is doubtful. Platyrhina and Platyrhinoidis are closely linked by the morphology of their spiny tubercles. Among the skates, the subgenus Raja (genus Raja) can be divided into three morphotypes. A new type of denticles is hereby described for Eastern Atlantic species. Interrelationships between subgenera of Raja are suggested by the arrangement and the morphology of thorns and dermal denticles. (Session 38, Monday June 17, Cabildo, 08:45) AES – Samuel Gruber Award KEYWORDS: DERMAL DENTICLES, SAWFISHES, GUITARFISHES, SKATES, SYSTEMATIC, COMPARATIVE ANATOMY

Dunn, K.A.
(KD) Dept. Wildlife and Fisheries Sciences, Texas A&M University

Phylogenetic relationships of the skates and rays inferred from the mitochondrial encoded 12S rRNA gene

Batoids have long been recognized as a monophyletic group sharing a long list of morphological synapomorphies. However, the relationships among the major clades (torpedinoids, pristoids, rajoids, rhinobatoids, and myliobatoids) are equivocal. This study examines these interrelationships using nucleotide sequences from the mitochondrial encoded 12S rRNA gene. The phylogenetic analysis tests the following two hypotheses: 1) Torpedinoids are the sister group of the remaining batoids. 2) Rhinobatoids are non-monophyletic, and separate components of this grade comprise the sister taxa of the rajoids and the myliobatoids. Morphological characters of the groups will be plotted on the molecular-based tree to examine the evolution of these characters. (Session 11, Saturday June 15, Cabildo, 08:30) AES – Samuel Gruber Award KEYWORDS: SKATES, RAYS, BATOIDS, 12S RRNA GENE, MITOCHONDRIA, MOLECULAR ANALYSIS

Economakis, A.E., and Lobel, P.S.
Boston University Marine Program, Marine Biological Laboratory, Woods Hole, MA 02543 USA

Aggregations of grey reef sharks, Carcharhinus amblyrhynchos, at Johnston Atoll, Central Pacific Ocean

Free-ranging female grey reef sharks, Carcharhinus amblyrhynchos, were observed aggregating at Sand Island, Johnston Atoll from March until late May in 1992, 1993, 1994 and 1995. Daily water temperatures were recorded at the aggregation area from 1993 to 1995. The annual aggregation cycle did not coincide with maximum or minimum annual water temperatures. During the 1994 aggregations, temperatures were recorded at 5 sites in the Atoll. The sharks aggregated most frequently and in highest numbers at the largest and shallowest site, which also contained the fewest underwater structures. The water temperature at this site was 1-2 C warmer than at neighboring sites and at a reef channel between the lagoon and the open ocean. The pattern of shark movements to and from the aggregation area was correlated with daily fluctuations of water temperature, light level, and tide level. During the 1994 aggregation period, five sharks were fed telemetry tags, and telemetry stations were deployed at three sites within the aggregation area. Individual sharks were tracked returning to the aggregation area for durations of one to five days. Sharks aggregated only during the day; they were not recorded or seen to return to the aggregation site during nighttime. (Poster Session 3, Monday June 17, Vieux Carre B, 01.) KEYWORDS: SEX SEGREGATION, AGGREGATION, SOCIAL BEHAVIOR, MIGRATIONS, HABITAT, ELASMOBRANCH, CARCHARHINUS AMBLYRHYNCHOS

Ellis, J., and Shackley, S.E.
School of Biological Sciences, University of Wales, Singleton Park, Swansea, SA2 8PP UK

The elasmobranch assemblage of the Bristol Channel and notes on their feeding habits

Ten species of elasmobranch fish were caught by otter trawl off the South Gower coast and, from commercial catches, at least an additional four species are known to occur. The most commonly caught species were Scyliorhinus canicula, Raja clavata and R.microocellata. Commercially important species within the study area include Raja spp.,Squalus acanthias and Lamna nasus. Triakid and scyliorhinid sharks are of little or no commercial importance. The diet of all commonly caught species was determined by the analysis of stomach contents. Piscivorous elasmobranchs included S. acanthias, L. nasus,Squatina squatina and Galeorhinus galeus, whereas most demersal species (Scyliorhinus spp., Raja spp.) predated on a variety of invertebrates and fish. Mustelusasterias predated almost exclusively on crustaceans. (Session 11, Saturday June 15, Cabildo, 11:30) KEYWORDS: ELASMOBRANCHII, DIETS, ABUNDANCE,SCYLIORHINUSRAJAMUSTELUSSQUALUSLAMNAGALEORHINUS

Ellis, J., and Shackley, S.E.
School of Biological Sciences, University of Wales, Singleton Park, Swansea, SA2 8PP UK

The biology of Raja microocellata

Raja microocellata is a little-studied rajid inhabiting sandy embayments in north-west Europe. The Bristol Channel is an area where the species is relatively abundant, being the second most important rajid, accounting for 35.3% (by numbers) and 37.8% (by biomass) of the rajid assemblage. Inshore waters are an important nursery area and the sex ratio of the juvenile population was 1:1. I-group fish ranged from 160-320mm TL and, during the summer, grew 0.91mm/day (0.98g/day). The diet was found to be primarily composed of Crangon crangon, mysids, teleosts and amphipods. Morphometrics are given for 50 specimens and the dentition, chondrocranium and claspers are described. (Session 38, Monday June 17, Cabildo, 09:30) KEYWORDS: RAJA MICROOCELLATA, DIET, NURSERY AREAS, SEX RATIO, DIET, MORPHOLOGY, DENTITION, GROWTH

Feldheim, K.A., Ashley, M.V., and Gruber, S.H.
(KF, MA) Department of Ecology and Evolution, UIC, Chicago, IL 60607-7060 USA; (SG) Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, Miami, FL 33149-1098 USA; (SG) Bimini Biological Field Station, 9300 SW 99th Street, Miami, FL 33176-2050 USA

Population genetics and mating system of a population of lemon sharks using microsatellites

DNA microsatellites are a powerful genetic tool for examining the population genetic structure and mating system of an organism. A genomic library for lemon sharks will be made and screened for microsatellite repeats, and primers for polymerase chain reaction amplification (PCR) will be made. Over 200 fin samples of juvenile and adult lemon sharksNegaprion brevirostris have been collected over the past years from Bimini lagoon in the Bahamas. PCR-amplification will be used to genotype every sample. Since these loci are highly variable, individuals can be distinguished from one another with the use of relatively few loci scored by size on a polyacrylamide gel. As microsatellite alleles follow Mendelian inheritance, determining parentage is straightforward. We propose to address the following questions concerning the Bimini population: 1) Do individual female lemon sharks use the Bimini lagoon as a nursery, returning there to give birth in multiple years? 2) Is there a skewed male mating success? 3) Are maternally related sibs sired by one or multiple males? 4) Is there evidence for inbreeding in the population? (Poster Session 2, Sunday June 16, Vieux Carre B, 24.) KEYWORDS: POPULATION GENETICS, MATING SYSTEM, LEMON SHARKS, MICROSATELLITES

Gadig, O.B.F.
UNESP – Universidade Estadual Paulista, Rio Claro, Sao Paulo, Brazil

Summarized data on the Squaliformes sharks from Brazil

The knowledgement of the Brazilian shark fauna is still scarce, due to small number of research and the large extention of the seashore. Available data only give attention to regional species. Concerning Squaliformes, the amount of current data are even more scarce, mainly because the habitat in which these species are commonly associated, e.g., Bathypelagic and Demersal, still are not vastly exploited by the Brazilian fisheries fleet, resulting in a small number of collected specimens for research. To date, about 17 species of Squaliform sharks are known to inhabit Brazilian waters. On the point of view of taxonomy the genus Squalus (with 5 nominal species related to this area) is the most troublesome. The species Euprotomicrus bispinatus and Zameus squamulosus were recorded only once. Recent studies based on long-line bottom fisheries, enabled the record of some species such as Centrocymnus cryptacanthus and Squalus asper. In the present study it is showed a revision of available data on the Brazilian Squaliformes, giving a key to their identification and discussion about the geographical distribution of same. (Poster Session 4, Tuesday June 18, Vieux Carre B, 15.) KEYWORDS: SQUALIFORMES, TAXONOMY, DISTRIBUTION, BRAZIL

Gadig, O.B.F.
UNESP – Universidade Estadual Paulista, Rio Claro, Sao Paulo, Brazil

Distribution and diversity of the Brazilian shark fauna

In the present work, it is discussed the geographical distribution as well the diversity of the Brazilian shark fauna. To date, 76 species belonging to 6 orders, 16 families and 34 genera were recorded. The Carcharhiniformes is the dominant group, (50% of the Brazilian species), followed by Squaliformes (22, 36%), Lamniformes (15%), Squatiniformes (5,26%), Hexanchiformes (3,94%) and Orectolobiformes (2,63%). The family which contains most of the species is Carcharhinidae (representing 27,63% of the total number of the species). Squalidae represents 21,05%, with the great majority occuring in Southern Brazilian region, possibly due to the suitable environmental conditions (of the 16 known species in Brazil, 15 occurring in this area). The Southeast region presents the largets number of species (80, 26% of the total), although the most diversified number of genera and families occuring in the Southern region (85, 29% and 93,75% respectively). The Northern and Northeast regions, present the smallest species diversity (39,47% and 48,68% respectively) in function of a fewer research number and the limitations of the fisheries fleet, when compared to Southern and Southeast regions. (Poster Session 4, Tuesday June 18, Vieux Carre B, 14.) KEYWORDS: DISTRIBUTION, DIVERSITY, SHARK, BRAZIL

Gelsleichter, J.
Virginia Institute of Marine Science, School of Marine Science, College of William and Mary, P.O. Box 1346, Gloucester Pt., VA 23062 USA

Skeletal structure and biomineralization in skates

A review of skeletal and non-skeletal mineralization in skates is presented. The structure and development of otoconia, dermal denticles and spinous denticle derivatives, feeding apparatus and calcified endoskeletal cartilage is discussed. Biominerals play essential roles in skate reproduction, feeding, locomotion, defense and structural support. These mineralized tissues are useful in systematics, age determination and the assessment of reproductive maturity. (Session 38, Monday June 17, Cabildo, 10:45) KEYWORDS: SKATE, SKELETON, CALCIFICATION, BIOMINERALIZATION, CARTILAGE

Gelsleichter, J., Cortés, E., Manire, C.A., Hueter, R.E., and Musick, J.A.
(JG, JAM) Virginia Institute of Marine Science, School of Marine Science, College of William and Mary, Gloucester Pt., VA 23062 USA; (EC, CAM, REH) Center for Shark Research, Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236 USA

Evaluation of toxicity and effectiveness of oxytetracycline and calcein as chemical markers in elasmobranch fishes

The effectiveness of calcein and oxytetracycline (OTC) as fluorescent markers of elasmobranch vertebrae and their toxicity were examined using the nurse shark,Ginglymostoma cirratum, and the clearnose skate, Raja eglanteria. Intramuscular injection of calcein at dosage levels of 25 and 5 mg/kg body weight (BW) produced distinct fluorescent marks in nurse shark and clearnose skate vertebrae, respectively. The higher dosage level of 25 mg/kg BW, in nurse sharks, produced several undesirable effects including physiological stress and rapid mortality. The lower dosage level of 5 mg/kg BW, in clearnose skates, appeared to be less toxic, yet was still associated with some animal mortality. Injection of OTC at a dosage level of 25 mg/kg BW produced fluorescent marks suitable for age validation in vertebrae from both species. Oxytetracycline injection was associated with some mortality in clearnose skates and abnormal serologic parameters in nurse sharks, perhaps suggesting chronic liver damage. Neither chemical appeared to affect short-term growth rates, but both may deleteriously affect fish health over a longer period of time. (Session 11, Saturday June 15, Cabildo, 08:45) AES – Samuel Gruber Award KEYWORDS: AGEING, AGE VALIDATION, CALCEIN, OXYTETRACYCLINE, VERTEBRAE, RAJA EGLANTERIAGINGLYMOSTOMA CIRRATUM

Goldman, K.
(KG) Department of Biology, San Francisco State University, 1600 Holloway Ave. San Francisco, CA 94132 USA; Steinhart Aquarium, California Academy of Sciences, Golden Gate Park, San Francisco, CA 94118 USA

Swimming depth and space utilization of white sharks, Carcharodon carcharias, at the South Farallon Islands, California

Acoustic telemetry techniques were used to obtain data on the space utilization, movement patterns, and swimming depths of four white sharks, Carcharodon carcharias, at the South Farallon Islands (SFI), California. Individuals ranged from approximately 3.7 m to 4.9 m in length. Sharks swam within about 10 m of the bottom to bottom depths of approximately 30 m, where they tended to stray more from the bottom. Main activity spaces (home ranges) ranged from 0.91 km{+2 to 6.52 km{+2, and were inversely related to the size of the individual. During the time tracked, larger individuals swam within particular areas around the islands whereas smaller individuals did not restrict their movements in the same manner. Site attachment index values along with the inverse relationship between total length and home range size and observations on other known individuals, indicate that larger sharks may prefer to search for prey in specific areas at SFI. These data provide evidence that white sharks at SFI may search for prey by traversing an area in a manner which maximizes coverage, and swim close to the bottom or at a distance far enough from the surface to remain cryptic from prey. (Session 24, Sunday June 16, Cabildo, 08:30) KEYWORDS: CARCHARODON CARCHARIAS, SOUTH FARALLON ISLANDS, ACOUSTIC TELEMETRY, SWIMMING DEPTH, MOVEMENTS, SPACE UTILIZATION, ACTIVITY SPACE, SEARCH BEHAVIOR

Grubbs, R.D.
School of Marine Science, Virginia Institute of Marine Science, College of William & Mary, Gloucester Point, VA 23062 USA

Recruitment Patterns and Nursery Ground Delineation for Carcharhinus plumbeus in Chesapeake Bay

Chesapeake Bay is the largest nursery in the western Atlantic for the sandbar shark,Carcharhinus plumbeus, a large coastal species which constitutes more than 2/3 of the sharks landed by the directed shark fishery along the Atlantic coast of the United States. As stocks of many large coastal species become severely depleted, informational needs concerning stock and recruitment relationships are paramount for proper management. In this study, preliminary delineation of the nursery for sandbar sharks in the lower Chesapeake Bay was developed and temporal recruitment dynamics were examined. The primary nursery is located in the high salinity waters in the southeast portion near the mouth. The overall distribution of juvenile sharks in the bay is more extensive on the eastern side as a function of increased salinity due to the effect of coriolis on incoming oceanic water masses and the influx of fresh water from the rivers on the western side of the bay. Mean juvenile sandbar shark abundances were positively correlated with surface temperatures (F=10.97;p<0.05). Recruitment to the nursery occurred in late May through June after surface temperatures rose above 18{+oC. Peak abundances were observed in July and decreased gradually as the water cooled. Migration from the bay occurred between late September and October after surface temperatures dropped below 20{+oC. More detailed nursery delineation and recruitment dynamics patterns are being developed. (Poster Session 2, Sunday June 16, Vieux Carre B, 25.) KEYWORDS: CARCHARHINUS PLUMBEUS, RECRUITMENT, TEMPERATURE, NURSERY, CHESAPEAKE BAY

Guallart-Furio, J., Aparici-Seguer, V., and Vicent-Rubert, J.J.
(JG-F, JJV-R, VA-S) Marine Biology Laboratory, Department of Animal Biology, University of Valencia, E-46100 Burjassot (Valencia), Spain

Biometric and histological analyses of finspines of Centrophorus granulosus(Bloch & Schneider), 1801 (Elasmobranchii, Squalidae) and its utility for age determination

Finspine structure of Centrophorus granulosus has been studied in order to evaluate its utility as an age determination tool for this species. In spite of external morphological differences, typical of the genus, the histological structure of spines is similar to that described for other Squalidae. Biometric analysis suggests that finspines continue to grow throughout life. Enamel, anterior dentine, external dentine and inner dentine show marks that could be interpreted as periodical discontinuities of growth, and will tentatively be considered as putative annual marks. However only in the case of the inner dentine it is possible to observe in a single preparation all the marks formed from the end of embrionic life to the last year of life of a given animal. A method of ring readings in inner dentine is proposed from transverse cuts of decalcified second dorsal finspines, stained with Mayer’s haemotoxylin. Requirements regarding cut location are discussed and explained with a schematic reconstruction of the development of finspines. Using this technique, preliminar readings of a group of finspines have been conducted out, fitted to a von Bertalanffy growth curve, and results contrasted with current knowledge of the biology of the species. (Poster Session 4, Tuesday June 18, Vieux Carre B, 21.) KEYWORDS: AGE DETERMINATION, GROWTH, FINSPINES, CENTROPHORUS GRANULOSUS, SQUALIDAE

Guallart-Furio, J., and Vicent-Rubert, J.J.
(JG-F, JJV-R, VA-S) Marine Biology Laboratory, Department of Animal Biology, University of Valencia, E-46100 Burjassot (Valencia), Spain

Changes in water, organic and inorganic matter composition during embryonic development in Centrophorus granulosus (Bloch & Schneider), 1801 (Elasmobranchii, Squalidae) from western Mediterranean: an assessment of mother- embryo nutritional relationships

Centrophorus granulosus is a bathyal shark that reproduces through aplacental viviparity. Its fecundity is one of the lowest described (only one embryo in the Mediterranean, ocassionally two in the Atlantic) and mature ovarian follicles reach one of the largest cellular sizes (>350 g) described for any animal species. Preliminary data suggest organic matter losses during development of about 50% (RANZI, 1932), the highest value reported for any elasmobranch. We have examinated the composition in water, organic and inorganic matter in a complete series of embryos, by drying and later incinerating separately the external yolk sac, eviscerated body, inner yolk sac, liver and digestive tube. Wet weight of uterine ova from females between 77 and 88 cm PRC ranges from 150 to 380 g, and is positively and significantly correlated with mother size. Size of full-term embryos can thus be expected to be larger in larger females. A graphical method is proposed to allow ponderal comparison between uterine ova and full-term embryos assuming the initial variability in uterine ova size. Results show an increase in total wet weight during development of 24-33%. Changes in percentual composition (from initial values) are: water + 96-98 %; organic matter – 19-34 %; inorganic matter + 96-123 %. Results show C. granulosus is a lecithotrophic species with scarce or no organic matter maternal contribution, although the female provides water and mineral compounds. Values of organic weight decrease are much lower than previously suggested, and similar to those described for oviparous species. These losses can be attributed to different expenses in energy during development, but probably also to changes in the composition of the organic matter, since high oil stores are present in the liver of full-term embryos. (Poster Session 4, Tuesday June 18, Vieux Carre B, 22.) KEYWORDS: EMBRYONIC DEVELOPMENT, LECITHOTROPHY, CENTROPHORUS GRANULOSUS, SQUALIDAE

Hazin, F.H.V., Lucena, F.M., Boeckman, C.E., Souza, T.S.A.L., and Menni, R.C.
SBEEL – Brazilian Elasmobranch Society

Preliminary study on the reproductive biology of the night shark Carcharhinus signatus (Poey, 1868) from the southeastern equatorial Atlantic Ocean

From October 1992 to December 1995, 411 night sharks, caught by the Brazilian longliners in the southwestern equatorial Atlantic, were examined. Of these 253 were males, from 116.5 to 211.5 cm total length (TL), and 178 were females, from 123.0 to 215.0 cm TL. Females were found in 6 different sexual stages: immature (116, 65.2%), maturing (33, 18.6%), preovulatory I (19, 10.7%), preovulatory II (4, 2.2%), pregnant (4, 2.2%), and ovulating (2, 1.1%). Immature females had undeveloped ovary. The maturing females had the largest ovarian follicle between 0.5 and 1.0 cm, in diameter, but none were vitellogenic. The preovulatory I specimens had a developing ovary, with vitellogenic follicles between 1.0 to 2.0 cm. In these specimens ovulation was close but not imminent. In the preovulatory II stage, ovulation was imminent. Their ovaries were fully ripe with large vitellogenic follicles of bright orange color. The pregnant females had 9 to 15 embryos. Of a total of 45 embryos, 18 were males and 27 were females. The two females that were ovulating had the ovary similar to the preovulatory II specimens and also eggs in their uteri. The 253 males were mature (56, 22.1%), maturing (52, 20.6%) and immature (145, 57.3%). The present data suggest that sexual maturity for males is reached at about 180 cm TL and for females at 190 cm TL, and that copulation probably happens from October to December. (Session 46, Monday June 17, Vieux Carre A, 01:30) KEYWORDS: REPRODUCTIVE BIOLOGY, NIGHT SHARK

Hazin, F.H.V., Mattos, S.M.G., Oliveira, P.G.V., Wanderley, J.A.M., Jr., Souza, T.S.A.L., and Zagaglia, J.R.
SBEEL – Brazilian Elasmobranch Society

Distribution and relative abundance of sharks off Pernambuco State, Brazil

From August 1994 to July 1995, 7 fishing cruises were done off Percambuco State, Brazil, over the continental shelf, using a bottom longline as a fishing gear. The fishing effort was concentrated mainly between 10 to 60 m depth. The catch per unit effort (CPUE) was calculated in terms of number and weight (kg) of fish caught per 100 hooks. Sharks represented 38.6% in number of total catch, with 73 specimens, and 28.3% in weight, with 2,947.4 kg. They belonged to the following species, with their percent of number and weight of the total shark caught and CPUE in number, respectively: blacknose sharkCarcharinus acronotus (43.8%, 11.9%, 0.17), sandbar shark Carcharinus plumbeus(34.2%, 43.1%, 0.13), nurse shark Ginglymostoma cirratum (8.2%, 15.8%, 0.03), bullshark Carcharinus leucas (4.1%, 16.5%, 0.02), tiger shark Galeocerdo cuvieri (4.1%, 3.7%, 0.02), Carcharinus porosus (1.4%, 0.3%, 0.01), blacktip shark Carcharinus limbatus (4.1%, 1.4%, 0.01), and hammerhead shark Sphyrna lewini (2.7%, 7.2%, 0.01). the blacknose shark was dominant in all months, with its highest abundance occurring in February, and at depth between 10 and 40 m. The relative abundance of the sandbar shark was highest in March and at depths between 50 and 60 m. (Session 46, Monday June 17, Vieux Carre A, 03:00) KEYWORDS: DISTRIBUTION, ABUNDANCE, SHARK

Hazin, F.H.V., Oliveira, P.G.V., Mattos, S.M.G., Souza, T.S.A.L., and Pinheiro, P.B.
SBEEL – Brazilian Elasmobranch Society

Reproductive biology of the blacknose shark Carcharinus acronotus (Poey, 1860) off Pernambuco State (Brazil)

From August 1994 to July 1995, 24 fishing cruises were carried out off Pernambuco State, Brazil, over the continental shelf, using bottom longline and gillnet as fishing gears. The catch included 44 specimens of the blacknose shark Carcharinus acronotus, 17 being males, ranging from 87.0 to 128.0 cm total length (TL) and 27 females, from 97.5 to 130.0 cm TL. Of the 17 males, 4 were sexually immature, TL from 87.0 to 94.0 cm, and 13, ranging from 104.0 to 128.0 cm TL, were clearly mature. Of the 27 females, 25 were adult specimens, ranging from 106.0 to 130.0 cm TL, and 2 were juvenile, from 97.5 to 101.0 cm TL. Of the 25 adult specimens, 4 were pregnant, 3 were preovulatory, 2 were ovulating and 16 were apparently sexually resting. All pregnant females had 4 embryos, with TL ranging from 25.5 to 45.5 cm, and a 1:1 sex ratio. The 3 preovulatory females had well developed ovaries, showing vitelogenic follicles, suggesting that they were close to ovulation. The 2 females that were ovulating had well devloped ovaries, with 6 and 7 vitelogenic follicles. Finally, the remaining 16 females seemed to be sexually resting, judging from the absence of any vitelogenic follicles in their ovaries. The distribution of the sexual stages along the months suggests that the blacknose shark begins pregnancy in April and gives birth in summer, after 8 to 9 months gestation. (Session 46, Monday June 17, Vieux Carre A, 02:45) KEYWORDS: REPRODUCTIVE BIOLOGY, BLACKNOSE SHARK

Hazin, F.H.V., Oliveira, P.G.V., Mattos, S.M.G., Souza, T.S.A.L., and Wanderley, J.A.M., Jr.
SBEEL – Brazilian Elasmobranch Society

Reproductive biology of the sandbar shark Carcharinus plumbeus (Nardo, 1827) off Pernambuco State (Brazil)

From August 1994 to 1995, 7 fishing cruises were done off Pernambuco State – Brazil, over the continental shelf, using a bottom longline. Twenty two specimens of the sandbar shark Carcharinus plumbeus were caught, 6 being males, with a total length (TL) ranging from 154.0 to 196.0 cm, and 16 females, ranging from 180.0 to 208.0 cm. All males were sexually mature, showing calcified claspers, measuring 21.3 cm on average, and well developed testes. All the 16 females were adult. Of these 7 were pregnant, 4 were sexually mature, 1 was maturing, 4 were apparently sexually resting. The number of embryos in the pregnant females ranged from 7 to 10. Of a total of 60 embryos found, 35 were males and 25 were females, with total length ranging from 7.5 to 59.5 cm. The 4 sexually mature females were probably close to ovulation, since they had well developed ovaries, with large vitellogenic follicles. Their oviducal glands were sectioned and examined by light microscopy for the presence of spermatozoa but none were found. The remaining 4 females showed flabby uteri and a spent ovary, indicating that they probably had given birth recently. The distribution of these sexual stages along the months, and information on embryo size, suggest that the sandbar shark off Ernambuco have a 12-month gestation in alternated years, with ovulation and birth taking place around February/March. (Session 46, Monday June 17, Vieux Carre A, 02:00) KEYWORDS: REPRODUCTIVE BIOLOGY, SANDBAR SHARK

Hazin, F.H.V., Zagaglia, J.R., Geber, F.O., Wanderley, J.A.M., Jr., and Mattos, S.M.G.
SBEEL – Brazilian Elasmobranch Society

A shark attack outbreak off Recife-PE, Brazil

From September 1992 to August 1995, 20 shark attacks have taken place off Recife, with 7 fatalities. Of these, 16 were surfing (2 fatalities) and 4 were bathing (5 fatalities). Environmental data, such as monthly average of wind direction and force, direction and speed of oceanic currents, sea water temperature, salinity, turbidity were collected. As a possible human influence, the maritime traffic at the Suape Port, built in 1989 and located south of Recife, was analyzed. There was a highly significant correlation between the monthly number of ships and the months when the attacks occurred at full and new moons. There was no attack in the second quarter of the year, maybe due to the rainy season, decrease in wind intensity and school period, when people usually don’t go to the sea very often. Most of the attacks occurred in the third quarter (over 40%), when the wind was strongest, coming from southeast, and the water was turbid. The results suggest that the shark attack outbreak was maily caused by the construction of the Suape Port, being aggravated by the southeast winds, which intensify the south-north coast current from Suape to Recife. (Session 46, Monday June 17, Vieux Carre A, 02:15) KEYWORDS: OUTBREAK, SHARK ATTACK

Hazin, F.H.V., Zagaglia, J.R., Souza, T.S.A.L., Oliveira, P.G.V., and Mattos, S.M.G.
SBEEL – Brazilian Elasmobranch Society

Distribution and relative abundance of the night shark Carcharhinus signatus(Poey, 1868) and the blue shark Prionace glauca (Linnaeus, 1758) in the southwestern equatorial Atlantic Ocean

From August 1986 to June 1995, catch data from Brazilian longliners operating in the wouthwestern equatorial Atlantic Ocean, from Natal-RN, Brazil, were collected and analyzed. Sharks of the genus Carcharinus, mainly the night shark C. signatus, and the blue shark Prionace glauca are the species most caught by this fishery, representing together over 90% of the total shark catch. The fishing area is located between “2{+oS” and “8{+oS” and “32{+oW” and “39{+oW”. The night shark was strongly domiant over shallow oceanic banks wher their abundance was highest. In the area between “35{+oW” and “39{+oW, where the banks are abundant, they represented more than 90% of the total shark catch, reaching less than 15% in the area located between “32{+oW” and “33{+oW”. On the other hand, the blue shark was much more abundant in oceanic areas, showing a pattern of distribution opposite to that of the night shark, reaching over 90% of the shark catches to the west of “32{+oW”. These data suggest that these shark species have an antagonic distribution, which certainly reduces theri competition for food, since they prey basically on similar prey items. (Session 46, Monday June 17, Vieux Carre A, 01:45) KEYWORDS: DISTRIBUTION, ABUNDANCE, SHARK

Heist, E., and Gold, J.
Dept. of Wildlife and Fisheries Sciences; Texas A&M University; College Station, TX 77843-2258 USA

Preliminary investigation of microsatellite loci in the sandbar shark, (Carcharhinus plumbeus)

Analysis of genetic population structure requires scoring of polymorphic genetic loci. Techniques most often used for this purpose include allozyme electrophoresis and analysis of polymorphic restriction sites in mitochondrial DNA. Studies using these techniques have demonstrated that many species of elasmobranchs exhibit low genetic variation, a situation that limits the power of these techniques and necessitates the scoring of large numbers of individuals. We detail here the application of a relatively recent technique, analysis of short tandem repeats of DNA (microsatellites) in the sandbar shark (Carcharhinus plumbeus), a species that exhibits extremely low allozyme and mitochondrial diversity. A genomic library of restriction fragments was screened with di-, tri-, and tetra- nucleotide repeat sequences to detect microsatellite loci. Several repeat motifs were identified and sequenced. Oligonucleotide primers for amplification of loci via polymerase chain reaction were developed. Polymorphism in microsatellite copy number was scored on denaturing polyacrylamide gels. Sandbar shark microsatellites, like those of other vertebrate taxa, are highly polymorphic. The utility of microsatellites for population studies in elasmobranchs and the conservation of loci detected in the sandbar shark across other species of sharks are discussed. (Session 18, Saturday June 15, Cabildo, 03:15) KEYWORDS: SANDBAR SHARK, CARCHARHINUS PLUMBEUS, POPULATION GENETICS, MICROSATELLITES

Henningsen, A.D., Hecker, B., Hampton, P., and Jones, R.T.
(AH) NAIB, Baltimore, MD and MEES Department, UMAB, Baltimore, MD 21201; (BH, PH) NAIB, Baltimore, MD 21202; (RJ) Department of Pathology, UMAB, Baltimore, MD 21201 USA

Survey of large coastal sharks in the Delaware bay by longline

For the past 15 years, the National Aquarium in Baltimore (NAIB) has been catching sharks for their collection using bottom set long-lines. NAIB has capture data from 9 collecting trips in June and July from 1986 to 1995. Only data on those sharks classified as large coastal species (LCS) under the Fisheries Management Plan for sharks will be presented. These species collected were sandbar Carcharhinus plumbeus, sandtigerCarcharias taurus, and dusky sharks, Carcharhinus obscurus. A total of 601 large coastal sharks were collected by long-lining. These catches were dominated by the sandbar shark (90.8% of the long-line catch). The highest catch per unit effort (CPUE) for sandbar sharks collected by long-line was 20 sharks per 100 hooks fished in 1995. (Session 04, Friday June 14, Cabildo, 02:15) AES – Samuel Gruber Award KEYWORDS: SHARKS, LONG-LINE, DELAWARE BAY, SANDBAR, SANDTIGER, DUSKY

Herdendorf, C.E., and Berra, T.M.
(CEH)Department of Zoology, Ohio State University, Columbus, OH 43210 USA; (TMB)Department of Zoology, Ohio State University, Mansfield, OH 44906 USA 

A Greenland shark Somniosus microcephalus from the wreck of the SS Central America at 2200 meters

In 1857 a three-masted, wooden-hulled steamship sank during a hurricane in 2200 m of water 440 km S-SE of Cape Hatteras, North Carolina. The 85-m ship was known to be carrying at least three tons of gold. A recovery project was begun in 1988 using the unmanned research submersible Nemo equipped with video and still cameras. Bait was set out at the wreck site to attract marine life. A 6-m long, male Greenland shark was photographed at the wreck site. The depth of 2200 m is 1000 m deeper than the maximum reported depth for this species, and is the deepest record for any species of large shark. The Cape Hatteras location is over 1000 km further south than the previously known Cape Cod record for Somniosus microcephalus. Video clips of the shark, deep-sea fishes and invertebrates, and the gold bars and coins will be shown. (Session 24, Sunday June 16, Cabildo, 08:45) KEYWORDS: GREENLAND SHARK, SOMNIOSUS, DEEP-SEA FISHES, SHIP WRECK

Hueter, R.E., Manire, C.A., Castillo-Geniz, L., Marquez-Farias, F., and Cortés, E.
(REH, CAM, EC) Center for Shark Research, Mote Marine Laboratory, Sarasota, FL 34236 USA; (LC-G, FM-F) Programa Tibur<o>n, Instituto Nacional de la Pesca, C.P. 03310, Distrito Federal, Mexico

Distribution and movements of juvenile sharks in coastal waters of the Gulf of Mexico

Surveys conducted since 1991 reveal at least 16 shark species give birth in coastal waters of the northeastern and southern Gulf of Mexico. This coastal Gulf shark fauna is dominated by placental, viviparous species of carcharhinids and sphyrnids. Pupping season varies by species and specific nursery area but tends to occur during late spring and early summer. Seasonal migrations of the young sharks out of primary nursery areas in fall are common and appear to involve mainly southern movements in the western Gulf and southern and/or offshore movements in the eastern Gulf. A tagging program concentrated in key nurseries of the eastern and southern Gulf is being used to follow long-term movements of the juvenile sharks. One of these nurseries is Laguna Yalahau, a shallow bay on the Yucatan peninsula in Quintana Roo, Mexico, where blacktip sharks (Carcharhinus limbatus) give birth beginning in May. At least some of the young-of-the-year (YOY) blacktips migrate out of the bay by October, moving easterly or westerly down the Yucatan coast. Recapture rate of these blacktips has been 14%, or about three times the rate in the eastern Gulf, and all of the Mexican recaptures have been by commercial fishermen. (Session 53, Tuesday June 18, Pontalba, 03:30) KEYWORDS: SHARK, NURSERY, JUVENILE, GULF OF MEXICO, YUCATAN, MIGRATION, TAGGING

Jensen, C.F., Branstetter, S., and Burgess, G.H.
(CFJ, SB) Gulf and South Atlantic Fisheries Development Foundation, Ste. 997, 5401 W. Kennedy, Tampa, FL 33609 USA; (GHB) Florida Museum of Natural History, University of Florida, Gainesville, FL 32611 USA

Characterization of the North Carolina commercial shark fishery during 1994 and 1995

An at-sea observer monitored 44 commercial shark fishing trips in the North Carolina area during 1994-95. This area contributed 20% of the U.S. Atlantic commercial quota over the two year period, and the program documented 6.1% of these landings. Eighty-nine longline sets, typically 13-14 miles long fishing 700-800 hooks, caught 4,697 sharks of which large-coastal (LC) species constituted 90% of the total. A CPUE for total sharks was 47.9 sharks per 10,000 hook-hr; LC CPUE was 41.1 sharks per 10,000 hook-hr. By number, the more common large-coastal sharks in the catch were: sandbar (Carcharhinus plumbeus) (65%; CPUE=23.9), tiger (Galeocerdo cuvier) (16%; CPUE=6.9), dusky (C. obscurus) (10%; CPUE=3.6), and blacktip (C. limbatus) (4%; CPUE=1.6) sharks. By number, landings of large-coastals were dominated by sandbar (79%), followed distantly by dusky (12%), and blacktip (7%) sharks. About 3/4 of the sandbar sharks were females, and length frequency data indicated less than 50% of the catch of either sex was mature. For dusky sharks, females constituted 51% of the catch, and length frequency data illustrated that 84% of the total catch (sexes combined) was immature. (Session 11, Saturday June 15, Cabildo, 09:30) KEYWORDS: SHARK, FISHERY,CARCHARHINUSGALEOCERDO, NORTH CAROLINA

Jensen, C.F., Natanson, L.J., and Branstetter, S.
(CFJ, SB) Gulf and South Atlantic Fisheries Development Foundation, Ste. 997, 5401 W. Kennedy, Tampa, FL 33609, USA; (LJN) NOAA/NMFS, 28 Tarzwell Rd., Narragansett, RI 02882-1199 USA

A preliminary estimate of age and growth of the bignose shark, Carcharhinus altimus, in the western north Atlantic Ocean

Age and growth of the bignose shark, Carcharhinus altimus, was estimated from seasonal bands formed in the vertebral centra of 37 individuals – 17 males and 20 females. Preliminary marginal increment analysis indicates annual band periodicity. Combined age at length data for both sexes produced von Bertalanffy growth function parameters of L{-l = 212 cm FL, K = 0.11, and t{-o = -3.78. The smallest size at maturity is reported at 182 cm FL for males and 190 cm FL for females. These lengths correspond to 13 years for males and 17 years for females. The oldest fish aged from vertebrae was a 23 year old male. Thus, the bignose shark appears to follow the general trend of slow growth and age at maturity exhibited by other members of the genus Carcharhinus. (Session 24, Sunday June 16, Cabildo, 11:15) KEYWORDS: AGE AND GROWTH, CARCHARHINUS ALTIMUS, BIGNOSE SHARK, VON BERTALANFFY

Joung, S.J., Chen, C.T., Clark, E., and Uchida, S.
(SJ,CC) Department of Fishery Science, National Taiwan Ocean University, 2 Pei- Ning RD, Keelung. Taiwan,Republic of China.; (EC) Department of Zoology, University of Maryland, College Park, MD 20742, USA; (SU) Okinawa Expo. Aquarium, Motobu-Cho, Okinawa Pref., Japan 905-03

Ovoviparity established in the whale shark, Rhincodon typus: 300 embryos found in one female

The whale shark, Rhincodon typus, is one of the largest creatures on this planet and the largest fish in the world. On 15 July 1995, a pregnant female was harpooned 2 miles off Tong Ho on the east coast of Taiwan. The shark was 10 m TL and 16 metric tons. About 300 embryos were found in the uteri. Many of the embryos had a yolks sac and were in egg cases. Most were free of their egg cases and without a yolks. Empty egg cases were found within the uteri. Thousands of small ova, each less than l cm in diameter, were found in the ovary. About 15 of the pups were alive and put into containers with sea water, however, only two still healthy, one in Japan, other in Taiwan. These pups measured 58~64 cm TL. The remaining 286 embryos were frozen. We were able to obtain 237 of embryos to determine the sex and measure the length frequency distribution. The sex ratio of all the embryos and pups available was 123:114. Three size classes were found: one class 42 to 52, one 52 to 58 and one 58 to 64 cm TL. (Session 24, Sunday June 16, Cabildo, 10:15) KEYWORDS: RHINCODONTIDAE, SIZES OF EMBRYOS, EGG CASES, REPRODUCTIVE ANATOMY, OVOVIVIPARITY, ELASMOBRANCH

Knight, D.P., Hamlett, W.C., Henderson, A., and Koob, T.J.
(DPK) King Alfred’s College, Winchester, UK; (WCH) Indiana University School of Medicine, Notre Dame, IN USA; (AH) University of Notre Dame, Notre Dame, IN; (TJK) Shriners Hospital, Tampa, FL USA

Subcellular structure of the shell gland in Raja erinacea and Raja eglanteria

This study utilizes light, scanning and transmission electron microscopy to examine the structure of the shell gland in skates. The gland is a kidney shaped thickening of the upper portion of each oviduct. Glands consist of dorsal and ventral, mirror-image halves that surround a dorsoventrally flattened lumen. Each half of the gland produces one of the two walls of the egg case. A series of transverse grooves extend across the gland. The cranial most region produces a jelly coating for the egg. The bulk of the transverse grooves are involved with production of egg case proteins and enzymes involved in their assembly. Secretory epithelial cells are columnar with supranuclear Golgi and prominent secretory vesicles. Secretion products are released into gland tubules and transferred to secretory ducts. Secretory products then pass between two baffle plates that deflect the material into distinct streams. The spinneret region assembles the secretory material before passage to the transverse grooves where lamellar assembly occurs. In the caudal region of the gland, elongate fibrils are added to the surface of the egg case. Sperm is present in several regions of the gland. (Poster Session 2, Sunday June 16, Vieux Carre B, 23.) KEYWORDS: SHELL GLAND, SKATE, OVIDUCT, EGG CASE, EGG

Koester, D.M., and Boord, R.L.
(DMK) Anatomy Department, University of New England, Biddeford, ME 04005 USA; (RLB) Department of Biology, University of Delaware, Newark, DE 19711 USA

Motor pathways to the electric organ of skates

The electric organ of skates consists of paired, longitudinal columns of electrocytes situated within the lateral hypaxial musculature of the tail. Dissections of Raja erinacea and Raja eglanteria specimens, macerated in nitric acid or stained with Sudan Black B, reveal that the electrocytes are innervated exclusively by segmental electromotor nerves. Each electromotor nerve is formed by small fascicles that branch from the ventral root of each spinal nerve at all levels of the electric organ. Horseradish peroxidase experiments were performed to identify the location and distribution of the spinal motoneurons which give rise to the electromotor nerves. The large multipolar electromotoneurons are evenly distributed among other motoneurons within the ventral column of gray of the spinal cord. Unlike most electric fish, the electromotoneurons of skates do not form a discrete spinal nucleus. Neurons within the inferior raphe nucleus of the medulla are labelled following small horseradish peroxidase injections into the ventral column of the spinal cord. These neurons are the origin of a descending spinal pathway to the electromotoneurons and presumably comprise a medullary command nucleus. (Session 44, Monday June 17, Cabildo, 02:00) KEYWORDS: SKATES, ELECTRIC ORGAN, ELECTROMOTOR NERVE, ELECTROMOTONEURONS, COMMAND NUCLEUS

Koob, T.J.
(TJK) Skeletal Biology Section, Shriners Hospital, Tampa, FL 33612 USA and Mount Desert Island Biological Laboratory, Salsbury Cove, ME 04672 USA

Biology of egg encapsulation in skates

Contemporary skates encapsulate fertilized eggs in unusually shaped, leathery capsules with remarkable physicochemical properties that harbor the developing embryo for the 6 month to 2 year incubation. The shell gland synthesizes, stores in cytoplasmic granules, then secretes a complex suite of structural proteins and enzymes which are subsequently mixed and assembled into a multi-laminate material within the gland lumen. Matrix sclerotization follows as the formed capsule moves into the uterus and involves an enzymatically catalyzed quinone tanning mechanism requiring uterine-derived oxygen. Minerals are incorporated in the capsule material in the shell gland and become organically bound during the tanning process. At oviposition, the capsule material exhibits a variety of extraordinary chemical properties including specific size-exclusion permeability, solid state enzymatic activities, a significant oxidation reduction potential, metal binding capabilities, immunity to bacterial attack and site-specialized adhesive structures. These chemical properties change after oviposition suggesting potential functions related to embryonic development and environmental conditions. Egg encapsulation in skates is thus a complex biochemical phenomenon resulting in a chemically active biomaterial which may have functions other than simple mechanical protection. These observations raise questions regarding the pleisiomorphic reproductive mode in elasmobranchs and the evolution of selachian oviparity. (Session 44, Monday June 17, Cabildo, 02: 15) KEYWORDS: RAJOIDEI, SKATE, REPRODUCTION, EGG CAPSULES

Koob, T.J., and Summers, A.P.
(TJK) Skeletal Biology Section, Shriners Hospital, Tampa, FL 33612 USA and Mount Desert Island Biological Laboratory, Salsbury Cove, ME 04672 USA; (APS) Organismic and Evolutionary Biology, University of Massachusetts, Amherst, MA 01003 USA

On the hydrodynamic properties of skate egg capsules

Skates lay eggs in rectangular capsules flattened in the dorso-ventral plane and equipped with curved horns emanating from each corner. While this unusual shape has evoked considerable speculation with respect to possible function, there has been no theoretical or empirical investigation of their shape-related properties. Egg capsules of several species of skates (R. erinaceaR. radiataR. sentaR. binoculata) were subjected to biologically relevant currents in a flow tank to investigate specific hydrodynamic properties. R. erinaceacapsules showed streamlined behavior with relatively low drag coefficients at particular capsule orientations. Hatched capsules filled with dye were subjected to defined current speeds to determine whether currents induced flow through the capsule via the slits located on the horns. The amount of dye removed from the capsule through a specific set of slits was directly related to current speeds between 6 and 20 cm/sec. Capsule orientation did not significantly alter rates of dye removal. However, orientation did affect through which horns dye exited the capsule. These observations establish that skate egg capsules are hydrodynamic. We speculate that the hydrodynamic properties may enhance survivorship to hatching by augmenting intra-capsular oxygen for the continually accelerating respiratory demands of the developing embryo. (Session 38, Monday June 17, Cabildo, 10:15) KEYWORDS: RAJOIDEI, SKATES, EGG CAPSULES, HYDRODYNAMICS

Lacy, E.R., and Reale, E.
(ERL) Department of Cell Biology and Anatomy, Medical University of South Carolina, Charleston, SC 29425 USA; (ER) Abteilung Elektronenmikroskopie, Medizinische Hochschule Hannover, D-30623 Hannover, Germany

Structure-function relationships of the little skate kidney

Elasmobranch fish have evolved a unique osmoregulatory strategy among marine vertebrates. These fish maintain plasma and body fluids hypertonic to their external environment. The elevated osmolality of their internal milieu is due mainly to the high concentrations of urea and trimethylamine oxide which account for up to 50% of the osmolytes. To maintain these levels, the kidney is highly efficient in conserving both compounds excreting from 1-10% only of that filtered. The architecture of the nephron reveals that it is one of the most complex among animals. The kidney consists of 2 zones: 1) sinus zone which receives both arterial and venous blood, and 2) bundle zone which receives only arterial blood and consists of unique nephron loops wrapped together in bundles, each of which is surrounded by a cellular sheath. Computer-assisted reconstruction showed each tubular bundle consisted of a renal counter-current system. Microscopical comparisons of kidneys from stenohaline freshwater stingrays which do not use urea as an osmolyte nor reabsorb it in the kidney and do not have a bundle zone suggests that the renal counter-current system functions to reabsorb urea in the skate. (Session 38, Monday June 17, Cabildo, 11:30) KEYWORDS: KIDNEY, SKATE, UREA, OSMOREGULATION

Last, P.R.
CSIRO Fisheries, PO Box 1538, Hobart 7001 Australia

Zoogeography and relationships of Australasian skates

The extant skate fauna of the Australian/New Zealand region and subAntarctic dependencies, with more than 50 species, has both high diversity and endemicity. It is comprised of 10 nominal supraspecific taxa, namely the rajid groups Bathyraja, Raja (represented by the subgenera AmblyrajaDipturusOkamejei and Rajella) and the arhynchobatid groups ArhynchobatisIrolitaPavoraja and Notoraja. Additional unnamed taxa at both specific and supraspecific levels also occur in the region and their most distinctive taxonomic features are discussed. The region is a radiation center for the family Arhynchobatidae and the New Zealand component of the fauna is dominated by an undescribed subgenus of Pavoraja. The Australian component, although well represented by arhynchobatids, is dominated by members of the genus Raja and shows little or no overlap in species composition with New Zealand skates. Important zoogeographic trends are discussed in relation to paleo-historical events and the present composition of the fauna. Relationships of Australasian skates and those of nearby regions are discussed in the light of new information. (Session 38, Monday June 17, Cabildo, 09:15) KEYWORDS: SKATES, AUSTRALIA, NEW ZEALAND, ZOOGEOGRAPHY, RELATIONSHIPS

Lowe, C.
Hawaii Institute of Marine Biology, UH, PO Box 1346, Kaneohe, HI 96744 USA

Tackling controversial conservation issues: Students can make a difference!

Students and young scientists can play a critical role in conservation issues. The first and most important step is simply getting involved. In many cases, students make great contributions to conservation issues by providing valuable data collected during their research. Unfortunately, they are seldom involved in the decision making processes of these issues because of their titles and/or age. The most challenging aspect in contributing as a student is establishing ones scientific credibility. This requires persistence, confidence, and objectivity. In addition, being an effective scientific advisor on conservation issues requires extensive background research, as well as an understanding of the socio-economic pressures involved. Scientists with these skills can become influential educators for policy makers and the public. (ASIH Environmental Quality Committee Workshop, Sunday June 16, UNO DC Room 215 A&B, 12:00 – 1:30) KEYWORDS: CONSERVATION, STUDENTS, EDUCATION

Lowe, C.
Hawaii Institute of Marine Biology, UH, PO Box 1346, Kaneohe, HI 96744 USA

Swimming metabolism and SDA of juvenile scalloped hammerhead sharks

Little is known about active metabolism of obligate swimming elasmobranchs, such as hammerhead sharks. I measured the oxygen consumption (VO2) of juvenile scalloped hammerhead sharks, Sphyrna lewini, swimming at different speeds in a Brett-type flume. Specific dynamic action (SDA) was determined by measuring VO2 of sharks in preabsorptive (10 hrs after eating) and post-absorptive states (96 hrs after eating) while swimming at different speeds. Mean VO2 ranged from 314 mg kg{+-1hr{+-1 at 0.4 body lengths per sec (L s{+-1) to 429 mg kg{+-1hr{+-1 at 1.2 L s{+-1. SDA accounted for a 20% rise in VO2. Shark pups in this study exhibited higher active metabolic rates (MR) than lemon, leopard, and dogfish sharks, but similar MR of bonnethead sharks. Power performance curves for shark pups in this study had lower slopes than those of non-obligate swimming species. These physiological characteristics may be attributed to the hammerheads more active lifestyle. (Session 18, Saturday June 15, Cabildo, 02:15) KEYWORDS: SCALLOPED HAMMERHEAD SHARK, ACTIVE METABOLISM, SDA, SWIMMING, SPHYRNA LEWINI


Luer, C.
(CL) Mote Marine Laboratory, Sarasota, FL 34236 USA

Embryonic development in the clearnose skate (Raja eglanteria)

Clearnose skates (Raja eglanteria) are found seasonally along U.S. coasts of the Gulf of Mexico and Atlantic Ocean and have proven to be extremely valuable models for elasmobranch development, not only because of their broad distribution, but also because of their ease of captive maintenance and tendency to breed and lay eggs in captivity. When maintained at 20° C, clearnose skate embryos develop at a reproducible and predictable rate, with fully formed offspring hatching after 85±6 days. On the day of laying, each yolk has a visible blastodisc, with migration of cells from the rim of the blastodisc forming the primitive streak by day 4 and gradual closure of the neural tube and head region by day 7. By 2 weeks, developing eyes, brain, gill arches, and myomeres are clearly visible and blood is circulating. By 4 weeks, pectoral fins extend laterally and begin their rostral migration, which is complete by week 6. External gill filaments proliferate during weeks 4-7 and are totally resorbed by week 8. Skin pigmentation characteristic of newborns is present by week 9 and external yolk is depleted by the time hatching occurs (approximately 12 weeks). Newly hatched clearnose skates average 13.7±0.5 cm total length and 9.4±0.5 cm disc width. (Session 44, Monday June 17, Cabildo, 02:45) KEYWORDS: RAJA EGLANTERIA, CLEARNOSE SKATE, EMBRYONIC DEVELOPMENT

Manire, C.A., Rasmussen, L.E.L., and Woods, J.E.
(CM) Center for Shark Research, Mote Marine Laboratory, 1600 Thompson Parkway, Sarasota, FL 34236 USA; (LR) Dept. of Chemistry, Biochemistry, and Molecular Biology, Oregon Graduate Institute, PO Box 91000, Portland, OR 97291 USA; (JW) Laboratory of Developmental Endocrinology, 2621 Tanglewood Drive, Sarasota, FL 34239 USA

Serum steroid hormone concentrations and immunocytolocalization in the testes of the bonnethead shark, Sphyrna tiburo

The male bonnethead shark, Sphyrna tiburoi>, is known to exhibit an annual cycle of testicular development and regression, with development beginning in the spring and peaking in the late summer in populations off the southwest coast of Florida. Serum concentrations of steroid hormones through an annual testicular cycle were measured by radioimmunoassay. Testosterone, dihydrotestosterone and progesterone were found to exhibit increasing concentrations during testicular development with significant peaks occurring concurrently with maximum testicular development. 17 -beta estradiol concentrations also showed significant changes, with peaks occurring at the beginning of testicular development, at times of maximum testicular development and at mating. Sites of testicular hormone production were examined utilizing immunocytochemical techniques at the time of maximum testicular development. Results indicated that the Sertoli cells, spermatozoa, and interstitial cells immunostained for steroid hormones. This differs from other workers’ in vitro steroid measurements from Squalus acanthias testicular cell cultures, which indicated steroid production by Sertoli cells only. (Session 18, Saturday June 15, Cabildo, 02:30) KEYWORDS: STEROID HORMONES, BONNETHEAD SHARK, SPHYRNA TIBURO, RADIOIMMUNOASSAY, TESTICULAR CYCLE, IMMUNOCYTOLOCALIZATION

Maruska, K.P., and Tricas, T.C.
(KM, TT) Department of Biological Sciences, Florida Institute of Technology, Melbourne, FL 32901-6988 USA

Ecological morphology of the peripheral mechanosensory lateral line in the Atlantic stingray, Dasyatis sabina

The functional morphology of the lateral line in relation to the ecology of elasmobranch fishes is essentially unknown. This study examined the anatomy, organization and innervation of mechanoreceptors in the Atlantic stingray Dasyatis sabina, a predator of small infaunal invertebrates, with emphasis on function in the capture of prey. Superficial neuromasts are arranged in bilateral rows along the dorsal midline and oriented to facilitate stimulus detection in the transverse plane. The dorsal interconnected canal subsystems have main canals that bear sensory neuromasts and also extensive neuromast-free lateral tubules that extend receptive fields towards the disk margin. An extensive, compliant ventral canal system along the midline, snout and mouth lacks surface pores. Vesicles of Savi are small discrete subdermal pouches located in bilateral rows along the ventral snout midline. It is hypothesized that 1) superficial neuromasts detect transverse water flow across the body caused by tidal currents, conspecifics or predators, 2) pored ventral canals detect water motion made by prey near the disk margin, and 3) non-pored canals and vesicles of Savi require direct contact of prey with the skin and function as touch receptors to guide exposed prey towards the mouth. (Session 04, Friday June 14, Cabildo, 02:45) AES – Samuel Gruber Award KEYWORDS: DASYATIS SABINA, LATERAL LINE, MECHANOSENSORY, NEUROMAST, STINGRAY

Mattos, S.M.G., Hazin, F.H.V., and Pedrosa, B.M.J.
SBEEL – Brazilian Elasmobranch Society

Economic feasibilty of a longline shark fishery off Pernambuco State – Brazil

The economic results of 7 fishing cruises, done from August 1994 to July 1995, using a bottom longline over the continental shelf of Pernambuco State were analysed. The objective was to verify if a longline fishery aiming at shark would be economically feasible for Brazilian artisanal boats. Sharks accounted for most of the sale, due to their heavy weight and to the high price attained by their fins (up to US$ 80.00/kg of dried weight). The best yield was achieved at depths between 50 to 60 m (US$ 32,78/100 hooks/day). Considering the most productive depth band, the best bait and the use of 500 hooks, the average yield for a commercial fishery should be around US$ 4,600/fishing trip (10 days), or about US$ 9,200.00/month. On the other hand, the expenses for a commercial fishing boat would be around US$ 3,000/trip or US& 6,000/month. Therefore, the net profit for an artisanal fishery aiming at shark would be about US$ 3,200.00/ month. These results indicate that a shark fishery would fare worse than the already existing lobster fishery (approximately US$ 5,511/month), but much better than the handline fishery (approximately US$ 1,000.00/month). Although an artisanal longline shark fishery seems to be economically feasible, before any such fishery is promoted, there should be a thorough study on the stock availability in order to assure a sustainable exploitation. (Session 46, Monday June 17, Vieux Carre A, 02:30) KEYWORDS: ECONOMIC FEASIBILITY, SHARK FISHERIES

McDavitt, M.T.
No Address given

The cultural significance of the sawfishes (Pristidae): a brief survey

Despite their obscure status in western societies, a comprehensive literature review has revealed that the sawfishes (Family Pristidae) rank among the most important elasmobranchs worldwide in terms of cultural representation. Frequenting shallow coastal and freshwater habitats throughout the tropics, these enormous distinctive batoids are regularly encountered near human settlements. The rostra of these animals have been utilized as weapons, tools, medicine, and remain favorite religious offerings throughout their range. Among tribal societies, sawfishes are associated with powerful totemic ancestors, initiation rites, piscine fecundity, and sword combat. To the Aztecs, the world itself had been formed from a titanic sawfish. Pristids have also appeared prominently in the iconography of several of the world’s major religions. During WWII, 27 submarines went to war emblazoned with sawfish emblems and the insignia of modern German naval commandos continues to depict pristids. Sawfishes currently adorn the currency of seven African nations. Exploited for their meat, oil, fins, rostra, and skins, significant fisheries for sawfishes have existed in Lake Nicaragua, Brazil, Pakistan, Thailand, the Philippines, and southern China. Sawfishes have inspired art, mythology, reverence, and warfare. Given the substantial cultural heritage of these poorly researched elasmobranchs, perhaps they will also inspire renewed scientific interest. (Session 18, Saturday June 15, Cabildo, 02:00) KEYWORDS: CULTURAL SIGNIFICANCE, PRISTIDAE, SAWFISHES

McEachran, J.D., and Dunn, K.A.
JDM and KAD: Dept. Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX 77843-2258 USA

Interrelationships of skates (Chondrichthyes: Rajidae)

Although there have been several recent phylogenetic studies of skates, there is little consensus concerning the interrelationships of supraspecific taxa (subgenera and genera). Furthermore, it has been suggested that the largest generic level taxon (Raja) is polyphyletic. A survey of characters relating to the neurocranium, hypobranchial skeleton, scapulocoracoid, pelvic girdle, claspers, electrocyte morphology, thorn pattern, and alar thorn ultrastructure were used to construct a data matrix for 28 taxa and 3 outgroup taxa. A parsimony analysis of these data produced 12 equally parsimonious trees that were 144 steps in length with a consistency index of 0.701. A strict consensus corroborates earlier phylogenetic hypotheses and further resolves some areas. The taxonomic implications of these relationships are discussed. (Session 38, Monday June 17, Cabildo, 08:30) KEYWORDS: CHONDRICHTHYES, RAJIDAE, SKATES, RAJA, MOROPHOLOGY, PARSIMONY ANALYSIS

Merson, R.R., and Pratt, H.L., Jr.
(RRM) Department of Biological Sciences, URI, Kingston, RI 02881 USA; (HLP) National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Northeast Fisheries Science Center, 28 Tarzwell Dr., Narragansett, RI 02882-1199 USA

Pupping and nursery grounds of the sandbar shark, Carcharhinus plumbeus, in Delaware Bay

A gill net study of Delaware Bay, a known sandbar shark Carcharhinus plumbeus nursery ground was conducted 12-18 July and 23 August to 2 September, 1995. Objectives were to tag neonates and juveniles on their nursery grounds, compile a baseline survey of the Delaware Bay nursery habitat, test the experimental gill net, and calculate CPUE of sandbars in Delaware Bay. A total of 199 sandbar sharks were captured (40 to 94 cm FL) at 6 of 12 stations. Sharks were captured on the south coast over mud bottom in waters with >28 ppt salinity and surface temperatures ranging from 24.7 to 28.5 C. In July and August, some sandbars up to 52 cm FL carried umbilical cord remains, and unhealed umbilical scars were observed on 60% of sharks up to 59 cm FL. This indicates that pupping occurs as late as August, and size at birth is equal to or less than 59 cm FL. Eight of 154 tagged sharks, at liberty from 5 to 40 days, were recaptured before 6 September 1995; all had traveled less than 11.2 km (mean 4.4 km). It appears that Delaware Bay is an important pupping and nursery ground for the sandbar shark. (Session 11, Saturday June 15, Cabildo, 08:15) AES – Samuel Gruber Award KEYWORDS: DELAWARE BAY, SANDBAR SHARK, CARCHARHINUS PLUMBEUS, NURSERY GROUNDS

Metcalf, S.J.
Address: None given

Quantitative morphology of the elasmobranch electrosensory hindbrain

Are cell numbers in the elasmobranch brain directly related to body size or do they reflect sensory specialization? Relative to body size, elasmobranchs have brains as large as those of birds, reptiles and some mammals. In mammals, a large brain to body size correlates strongly with life history strategies. The biological significance of this neural trend in elasmobranchs is unknown (Northcutt, 1989). The electrosensory hindbrain, including the lateral line lobes and corpus cerebelli, varies significantly for a given body size. The electrosensory dorsal nucleus (DON) and corpus cerebelli are more prominent in Galeomorphs and some Myliobatiformes than other shark orders. These differences have not been quantified nor have the relationships of atrophied brain structures to factors such as sensory function, been tested. An unbiased estimate of neuron numbers in the electrosensory hindbrain was obtained using the stereological disector. Five individuals from 5 shark species (Prionace glaucaGaleorhinus galeusIago omanensis, Squalus acanthias and Cephaloscyllium isabella) were sampled. Results were analysed using General linear ANOVA models with mulitple comparison tests. Preliminary results show a strong effect of body size and taxonomy upon cell numbers. Results of secondary sensory neurons are pending. Neuron numbers are an important determinant of neural function, and consequently of behaviour. Data from this study will contribute to the theoretical modelling and understanding of electrosensory function. Northcutt, R.G. 1989. Brain variation and phylogenetic trends in elasmobranch fishes. The Journal of Experimental Zoology Supplement 2:83- 100(Session 11, Saturday June 15, Cabildo, 11:15) KEYWORDS: ELECTRIC SENSE, CEREBELLUM, DORSAL NUCLEUS (DON), TOTAL NEURON NUMBER, STEREOLOGY, PURKINJE CELL, GRANULE CELL, STELLATE CELL

Michels, S.F., Henningsen, A.D., and Jones, R.T.
(SM) Delaware Division of Fish & Wildlife, DNR & EC, Little Creek, DE 19961 USA; (AH) NAIB, Baltimore, MD 21202 USA; (RJ, AH) Department of Pathology, UMAB, Baltimore, MD 21201 USA

A trawl survey of sharks in the Delaware Bay

Over the past 30 years the Delaware Fish & Wildlife Division has been conducting coastal finfish assessment surveys of the Delaware Bay using a 30-foot (9.1 m) otter trawl. These surveys have been broken up into 3 six year periods (1966-71, 79-84, 90-95) Tows (20 min) were made at 9 fixed stations monthly for the 18 years. Although these surveys were designed to monitor trends in abundance and distribution of teleosts, information regarding the abundance and distribution of elasmobranchs in the Delaware Bay was obtained. Such information is important in developing specific population studies for elasmobranchs. This is a report of the sharks collected in these surveys. The most abundant shark species was the smooth dogfish (Mustelus canis). A total of 11,359 individuals were collected and they comprised 91.01% of the total sharks collected. Other sharks collected were: spiny dogfish (Squalus acanthias), sandbar (Carcharhinus plumbeus), sandtiger (Carcharias taurus) and the Atlantic angel shark (Squatina dumeril). A total of 971 spiny dogfish and 141 sandbars were collected. Sandbars were present in the Bay from May to October with August having the highest catch rate. This shark was found at 8 of the 9 stations surveyed. The highest annual sandbar density of 0.56 per nautical mile (NM) was in 1974 and the density for 1995 was 0.07/NM. (Session 11, Saturday June 15, Cabildo, 11:45) KEYWORDS: SHARKS, POPULATION, DELAWARE BAY, SMOOTH DOGFISH, SPINY DOGFISH, SANDBAR, SANDTIGER

Mollet, H., O’Sullivan, J., and Welsh, J.
Monterey Bay Aquarium, 886 Cannery Row, Monterey CA 93940, USA

Morphometrics, feeding, growth, litter data, and distribution of the pelagic stingray, Pteroplatytrygon violacea. More questions than answers?

Fifteen pelagic stingrays were used for a short-term feeding and growth experiment from March 1 to October 18, 1995 in a 3 m diameter tank (T = 17.8C) at the Monterey Bay Aquarium. Stillborn litters of 3 and 1 were observed in this tank on Sept. 7 and 19, respectively. Additional birth data for 12 litters from four aquaria in Japan, Spain, and California, born between October and March (1984-1995), and field data of 38 specimens in the SIO collection (1953-1990) were available. We report morphometrics, feeding, and growth data of captive pelagic rays. The litter data suggests different reproductive parameters for pelagic stingray populations in the Pacific, Atlantic, and the Mediterranean Sea. We propose that the eastern Pacific population gives birth in winter far off the coast of Central America and then moves to higher latitudes nearer the coast. (Session 24, Sunday June 16, Cabildo, 10:30) KEYWORDS: PELAGIC STINGRAY,PTEROPLATYTRYGON VIOLACEADASYATIS VIOLACEA, POPULATION, DISTRIBUTION, MORPHOMETRICS, FEEDING, GROWTH, REPRODUCTIVE PARAMETERS

Motta, P., and Wilga, C.
(PM, CW) Department of Biology, University of South Florida, Tampa, FL 33620 USA

Comparative functional morphology of the suspensoria of squaloid and carcharhinoid sharks

Squaliform and carcharhiniform sharks differ in their palatoquadrate- neurocranial articulation, and hyostylic jaw suspension. During upper jaw protrusion in Squalus acanthias the orbital processes slide ventrally through thin, sleeve-like ethmopalatine ligaments. The ethmopalatine ligaments run from the orbital processes to the edges of the ethmopalatine groove. The orbital processes and skin provide support to the anterior ends of the protruded palatoquadrate cartilages. The laterally directed hyomandibulae, which brace the posterior end of the jaws, pivot anteroventrally during palatoquadrate protrusion. Labial cartilages contribute to a circular mouth opening. Negaprion brevirostris has short orbital processes of the palatoquadrate that sit in shallow orbital notches. The thick elastic ethmopalatine ligaments fold on themselves when the upper jaw is retracted. During protrusion, the ethmopalatine ligaments unfold, the anterior ends of the palatoquadrate cartilages move anteroventrally away from the chondrocranium, and the distal ends of the hyomandibulae pivot anteroventrally. The hyomandibulae brace the jaws posteriorly, and only the ethmopalatine ligament, muscles, and the skin brace the jaws anteriorly. The protrusible, laterally enclosed mouth of the dogfish is used for both suction and bite captures of its prey, whereas, the lemon shark uses its protrusible upper jaw primarily to ram capture and bite its prey. (Poster Session 4, Tuesday June 18, Vieux Carre B, 02.) KEYWORDS: CARCHARHINOID, SQUALOID, PALATOQUADRATE, JAWS, SUSPENSORIUM, PROTRUSION, HYOMANDIBULA, FEEDING, SQUALUS ACANTHIASNEGAPRION BREVIROSTRIS

Musick, J.A., Grogan, E.D., and Lund, R.
(EDG) St. Joseph’s University, Biology Dept., 5600 City Ave.,Philadelphia, PA 19131 USA; (RL) Adelphi University, Dept. of Environmental Science, Dept. of Biology, Garden City, NY 11530 USA

A reevaluation of the higher systematic relationships of the Chondrichthyes

Higher systematic analyses of the cartilaginous fishes are few are far between compared to those of teleostean and other fishes. This situation is often attributed to a lower diversity of the modern members of this group and the paucity of data upon which a selachian and holocephalan sistergroup status could be based. However, various discoveries of many well preserved Paleozoic and Mesozoic forms indicates that the diversity of earlier chondrichthyan fishes was so extensive as to be arguably comparable to that of the recent teleosts. Consequently, the introduction of large numbers of new taxa during the last 30 years requires a reanalysis of the higher systematics of the chondrichthyans, particularly in relation to the Holocephali, cochliodonts, and the status of the Paraselachii. A cladistic analysis is presented for the cartilaginous fishes, with an emphasis upon the relationships of the modern Euselachii and Holocephali to the Paleozoic and Mesozoic paraselachians and holocephalans. In presenting this analysis and addressing the details of the higher classification of “Chondrichthyes”, our review of the literature revealed that Smith-Woodward’s monumental 1889 work on the classification of piscean vertebrates represents the last significant intensive effort to integrate fossil and extant data into a systematic analysis of the cartilaginous fishes and that the commonly accepted definitions of the Class Chondrichthyes and subordinate taxa are mired in confusion. The historical usage and interpretation of the taxonomic units Chondrichthyes, Elasmobranchii, Selachii, and Holocephali are chaotic and rooted in misinterpretations or misdiagnoses of features of suspensoria and fin structure. Consequently, we propose a classification which advances chondrichthyan systematic analyses by (1) combining information for both extant and fossil species, including that afforded by new cochliodont Holocephali and select Paraselachii; (2) refining taxonomic nomenclature and its usage; and (3) reassessing and redefining critical characters and character states. (Session 24, Sunday June 16, Cabildo, 09:00) KEYWORDS: HIGHER SYSTEMATICS, CHONDRICHTHYES, HOLOCEPHALI, PARASELACHII, COCHLIODONTS, FOSSIL, EXTANT

Nakaya, K.
Faculty of Fisheries, Hokkaido University, Hakodate 041, Japan

Megamouth shark Megachasma pelagios has a white lip

In November 1994, a first female specimen of the megamouth shark (4,710 mm TL, 790 kg) was found stranded on a sandy beach at Fukuoka, Japan, and secured by Marine World Umino-nakamichi. This specimen is being investigated from various view points, and morphologically this female did not differ greatly from the descriptions of other mature males. However, a white-colored band was found along dorsal margin of upper jaw. This band is about 4 cm in width and stretches transversely on snout a little below between right and left nostrils. Eight individuals of the megamouth shark are known to date, but nothing has been described about this white band. Investigation was made on available six megamouth specimens, and the white band was confirmed to exist in all of them. This white band is very conspicuous, sharply demarcated by black areas. When the upper jaw is fully retracted, this band is hidden and can be scarcely seen from the outside. However, this white band becomes remarkably prominent when the upper jaw is protruded. In addition, as this white area is located on anterior face of snout, it may play some important role in their life. (Session 11, Saturday June 15, Cabildo, 10:45) KEYWORDS: FIRST FEMALE, MEGAMOUTH SHARK, MEGACHASMA PELAGIOS, WHITE BAND, FUNCTION

Neer, J.A.
(JN) Moss Landing Marine Laboratories, P.O. Box 450, Moss Landing, CA, 95039 USA

Aspects of the reproduction of the Pacific electric ray, Torpedo californica (Ayres) in central and southern California

The Pacific electric ray, Torpedo californica (Ayres), is the only representative of the family Torpedinidae located off the California coast. Characterized as ovoviviparous, they have been used extensively in biomedical and neurophysiology research, despite lack of knowledge about much their natural history. My research goal is to determine if Torpedo californica have traits typical of most elasmobranchs (large size at first reproduction, low fecundity, long gestation, and slow growth); a combination of characteristics which make them easily susceptible to overexploitation. The objective of this portion of a larger study was to determine the relationship between size and reproductive status. Torpedo californica specimens were collected from central and southern California from July 1994 to January 1996. Reproductive status of males was determined using clasper length/disc width relationships, degree of clasper calcification, and the degree of coiling of the vans deferens; all of which indicated that males become mature at 400 mm disc width. Female sexual maturity was determined using uterine width and ovarian egg diameter relationships with disc width. A maximum fecundity estimate, obtained utilizing egg and ova number and the examination of a pregnant female, was determined to be 17. (Poster Session 4, Tuesday June 18, Vieux Carre B, 05.) KEYWORDS: REPRODUCTION, ELASMOBRANCH,TORPEDO CALIFORNICA, ELECTRIC RAY

Nelson, D.R.
Department of Biological Sciences, California State University, Long Beach, CA 90840 USA

Sound playback: a potential tool for fishery-independent assessment of pelagic shark populations

It has been known for years that sharks can be attracted to a transducer emitting low-frequency sounds. Attracted sharks can thus be identified and counted. Previous sound-playback studies have mainly involved topical reef species of the Florida/Bahamas and Indo-Pacific regions, but no full studies have been conducted in temperate waters. Preliminary trials indicate at least one temperate pelagic species, the shortfin mako, Isurus oxyrinchus, is acoustically attractable. Present experiments off southern California are testing the usefulness of the playback technique for obtaining needed fishery- management data on shark abundance, sizes, and sex ratios. Data will be compared to other fishery and fishery-independent assessment methods such as attraction by bait, research longlining, and sport and commercial landings. (Session 24, Sunday June 16, Cabildo, 08:00) KEYWORDS: ACOUSTIC ATTRACTION, SOUND PLAYBACK, SHORTFIN MAKO, ISURUS OXYRINCHUS

New, J.G.
Dept. of Biology & Parmly Hearing Institute, Loyola University Chicago, Chicago, IL 60626 USA

Organization of octavolateralis pathways in the skate brain

The octavolateralis senses in elasmobranch fishes comprise electrosensory, mechanosensory lateral line, auditory, and vestibular modalities. The central nervous system pathways of these senses are composed of parallel lemniscal nuclei and related tracts ascending from the medulla through the telencephalon. Afferent fibers of the lateral line nerves (electroreception and mechanosensory lateral line) and the octaval nerve (auditory and vestibular afferents) terminate in a tier of nuclei located in the alar medulla. Studies on the electrosensory nuclei of the hindbrain and cerebellum indicate that a significant function of neural processing at this level of the neuraxis is the suppression of reafferent interference. In the midbrain optic tectum and lateral mesencephalic nucleus, a somatotopic map of the electrosensory periphery is aligned with the retinotectal visual map. Although little is known about the nature of sensory processing at levels higher than the midbrain other than the representation of the different modalities in different nuclei, the similarities in pathway organization and the cytoarchitecture of nuclei associated with the various octavolateralis modalities argues for similarities in neural processing strategies, even though these senses detect physically dissimilar environmental stimuli. (Session 38, Monday June 17, Cabildo, 11:15) KEYWORDS: RAJA, ELECTRORECEPTION, LATERAL LINE, ELASMOBRANCH, AUDITORY, VESTIBULAR SENSE

Newton, M.
MBF Division, RSMAS-University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149 USA

Heterodonty and the role of morphometrics in the study of the phylogeny of the white shark, Carcharodon carcharias

Heterodonty, the difference in tooth structure within an individual of a species, causes significant problems when studying evolutionary change using fossil shark teeth. In the white shark, Carcharodon carcharias, ontogenetic, dignathic and monognathic variation can mask specific changes in the teeth through time. Unless tooth position can be identified, it is impossible to determine absolutely if an isolated tooth can be used for study of evolutionary variation. Unfortunately, most fossil shark teeth are isolated from the original jaw and neighboring teeth. Heterodonty thus limits the paleontologic information one can extract from these teeth. Morphometrics is the study of covariance of biological form. Recently, multivariate statistics and morphometrics have been used to remove intraspecific heterodonty and separate morphologically similar teeth of closely related species. Based on this work, a principal component analogue called Relative Warp Analysis is being used to analyze and compare sets of modern C. carcharias teeth with one five million year old natural set and one three million year old associated set to determine how this species has changed through time. This information is useful in determining whether or not isolatedCarcharias teeth are indeed from the modern species or from a closely related, but separate, lineage. (Poster Session 4, Tuesday June 18, Vieux Carre B, 18.) KEYWORDS:CARCHARODON CARCHARIAS, HETERODONTY, MORPHOMETRICS, PHYLOGENY

Norman, B.M.
School of Biological and Environmental Sciences, Murdoch University, South St., Murdoch, W.A., 6150. Australia 

The whale sharks Rhincodon typus of Ningaloo Reef, Western Australia – A preliminary study

The rare whale shark Rhincodon typus aggregates in large numbers each year at Ningaloo Reef, Western Australia. A preliminary study began in 1995, between the months of March and July, in an effort to learn the effects of the associated tourism industry on the whale sharks at this location. A limited repertoire of shark behaviours was defined. In water, observations were conducted from commercial charter boats throughout the season, and the sex, size, and behaviour of individual whale sharks was recorded. Of the animals sexed, 75% were male, and clasper morphology suggested the majority were immature. An identification library using photographs of individual sharks has been initiated, and a return of some recognisable animals is evident. (Session 04, Friday June 14, Cabildo, 03:30) AES – Samuel Gruber Award KEYWORDS: WHALE SHARK, NINGALOO REEF, BEHAVIOUR

Piermarini, P.M., Pabst, D.A., and McLellan, W.A.
(PM) Department of Zoology, U of Florida, Gainesville, FL 32611, USA; (DP, WM) Department of Biological Sciences, UNC-Wilmington, Wilmington, NC 28403 USA 

Functional morphology of dorsal fins from sharks in the families Carcharhinidae and Sphyrnidae

In a swimming shark, the dorsal fin is a key hydrodynamic control surface that experiences the deforming forces of bending, shear, lift, and drag. Shark dorsal fins, therefore, must be designed to resist such forces. The biomechanical functions of internal supporting structures in these fins have yet to be examined. The goals of this study were to describe the morphology and function of the internal supporting structures found in shark dorsal fins. Anterior dorsal fins from five species of sharks (3 Carcharhinidae, 2 Sphyrnidae) were removed and dissected. Dissections revealed a consistent arrangement of supportive structures. Basal elements of the fin consisted of medial cartilaginous rods (pterygiophores) which resisted bending and drag forces. The pterygiophores were surrounded laterally by segmented muscle masses. Myosepta connected the lateral surfaces of the fin, and may be involved in the resistance of both shear and lift forces. Distally, the lateral muscle masses were replaced by layers of small, stiff collagenous rods (ceratotrichia), that appear to resist bending forces. Furthest distal from the base, the fin was only composed of ceratotrichia intertwined in a connective tissue matrix. This connective tissue matrix may also be involved in resisting lift and shear forces. (Poster Session 2, Sunday June 16, Vieux Carre B, 17.) KEYWORDS: SHARK, SWIMMING, DORSAL FIN, FUNCTIONAL MORPHOLOGY, BIOMECHANICS, FIN SUPPORTING STRUCTURES, PTERYGIOPHORES, CERATOTRICHIA

Plizga, C., Burgess, G.H., and Branstetter, S.
(CP,GHB) Florida Museum of Natural History, University of Florida, Gainesville, FL 32611 USA; (SB) Gulf and South Atlantic Fisheries Development Foundation, Ste. 997, 5401 W. Kennedy, Tampa, FL 33609 USA

Monitoring the 1995 commercial shark fishery off the East Coast of Florida

The 1995 directed shark fishery off Florida’s east coast was monitored by an at- sea observer on 22 fishing trips. We monitored about 3.7% of the total catch from the region, which produced 21% of the U.S. Atlantic/Gulf of Mexico catch in 1994. The 71 observed sets typically utilized six miles of longline and 521 hooks. Over 3,500 sharks were captured, resulting in a CPUE of 136.7 sharks per 10,000 hook-hr. Small coastal (SC) sharks were a prominent target of the fishery, representing 61% of the fish landed. The Atlantic sharpnose shark (Rhizoprionodon terraenovae) comprised 81% of the SC catch. Large coastal (LC) sharks made up 75% of the landing by weight. Sandbar (Carcharhinus plumbeus; 49%) and blacktip (C. limbatus; 38%) sharks contributed 87% of the LC landings by number. The LC CPUE of 33.2 sharks per 10,000 hook-hr primarily reflected the abundances of sandbar (41% of LC catch) and blackip (30% of LC catch) sharks, which had CPUE’s of 11.6 and 11.5 per 10,000 hook-hr, respectively. Sandbar sharks surveyed were largely (56%) males, while the blacktips were mostly (59%) female. Analysis of length frequency data indicates that 45% of the sandbars and 54% of the blacktips caught were mature. (Session 11, Saturday June 15, Cabildo, 09:00) KEYWORDS: SHARK, FISHERY, RHIZOPRIONODON TERRAENOVAE,CARCHARHINUS PLUMBEUSCARCHARHINUS LIMBATUS, FLORIDA

Pratt, H.L., Jr., and Carrier, J.C.
(H.L.P., JR.) NOAA/NMFS, Narragansett Lab, 28 Tarzwell Drive, Narragansett, RI 02882 USA; (J.C.C.) Department of Biology, Albion College, Albion, MI 49224 USA

Tagging techniques for the underwater identification of sharks

Observations of shark reproductive behavior necessitated the development of a visual marking methodology for identification of sharks involved in mating events. Field tests of the NMFS dart tag showed that addition to the monofilament of contrasting plastic sleeves and beads arranged in a simple code is an effective solution for diver identification of the subject shark. A short streamer of brightly colored latex tubing added to the dart tag capsule makes the tag even more visible. Tags are delivered to the shark underwater at the tip of a shaft driven by a speargun. A single-hole rubber laboratory stopper limits penetration to 6 cm. The spear mounted tag must be released between 40 and 80 cm from the nurse shark for proper penetration. Tags serve three purposes: 1) brightly colored tags allow identification of participants in group events, 2) tags from previous years confirm site specificity, and 3) if the sharks are recaptured by fishermen, the capsule containing the NMFS return request ensures that recapture data are reported. Since 1992, we have tagged 27 reproductively active male and female nurse sharks and are able to recognize nine others by significant body markings. Repeat sightings have been numerous during mating season. (Session 46, Monday June 17, Vieux Carre A, 03:30) KEYWORDS: TAGGING, NURSE SHARKS, MATING, RECAPTURE, REPRODUCTION,


Pratt, H., Jr., and Natanson, L.J.
(LJN) NOAA/NMFS, 28 Tarzwell Dr., Narragansett, RI 02882 USA

Effect of temperature an band deposition in the little skate, Raja erinacea

Laboratory experiments were conducted to determine the effects of temperature on vertebral band deposition in the little skate, Raja erinacea. Skates, injected with the antibiotic tetracycline as a biological marker, were maintained in aquaria for one year. Band deposition patterns from skates kept under fluctuating temperature conditions were compared to depositions from skates kept under constant conditions; all other factors were the same. No effects of temperature on band deposition were apparent and annual band deposition was confirmed. (Session 38, Monday June 17, Cabildo, 11:00) KEYWORDS:RAJA ERINACEA, LITTLE SKATE, TETRACYCLINE, BAND DEPOSITION

Sadovy, Y., and Burgess, G.H.
(YS) Department of Ecology and Biodiversity, The University of Hong Kong, Pok Fu Lam Road, Hong Kong; (GHB) Florida Museum of Natural History, Gainesville, FL 32611 USA

Shark attack in Hong Kong

Hong Kong is not normally associated with shark attack; in the last fifty years there have been fourteen recorded attacks in Hong Kong waters. However, following six, and possibly more, fatal attacks in the last five years, all exhibiting an apparent seasonality and largely confined to Hong Kong’s eastern waters, efforts were concentrated on examining available meteorological and oceanographic data, beach attendance records and coastal activities in an attempt to establish attack correlates. Most attacks occurred during well- defined periods at the beginning and end of the summer, although these periods do not appear to correlate with intensity of water use. All attacks (except one) occurred when sea surface water temperature rose above about 24({+o)C (annual range 16({+o)C-28({+o)C) and were associated with marked changes in wind speed and direction, from off- to on-shore; rainfall patterns may also be involved. The species involved has not been confirmed in any attack but the tiger shark, (Galeocerdo cuvier) has been implicated in several incidents by sightings and autopsy reports. Hong Kong has now installed shark ‘exclusion’ nets to protect swimmers and does not support post-attack hunting. (Session 18, Saturday June 15, Cabildo, 01:45) KEYWORDS: SHARK ATTACK, HONG KONG, TEMPERATURE, SHARK EXCLUSION NETS

Sisneros, J.A., Tricas, T.C., and Luer, C.A.
(JAS, TCT) Department of Biological Sciences, Florida Tech, Melbourne, FL 32901-6988 USA; (CAL) Mote Marine Laboratory, Sarasota, FL 34236 USA

Response properties and function of the skate electrosensory system during ontogeny

The electric sense of skates is an important sensory modality used for the detection of prey and conspecific electric organ discharges (EODs) produced during social behavior. This study determined the response properties of electrosensory primary afferent neurons in embryo, juvenile, and adult clearnose skates (Raja eglanteria) and whether frequency response changes with age. Additionally, we tested the hypothesis that the adult electrosensory system is optimized for electric communication. Single unit discharges of electrosensory primary afferent neurons were recorded from three skate size classes: prehatch embryos (8-11 weeks, n = 9), juveniles (1-8 months, n = 5), and adults (>2 yrs, n = 4). Resting discharge rate and neural gain increased 3 and 5 fold, respectively, from embryos to juveniles but did not change among juveniles and adults. Peak frequency sensitivity increased from embryos (1-2 Hz) to juveniles (4-6 Hz) but decreased from juveniles to adults (2-3 Hz). EOD pulse rate (mean = 2.5+1.1 SD Hz, n = 34) produced during mating activity is aligned with peak frequency response of the adult skate electrosensory system. We propose that the match between peak frequency sensitivity and EOD pulse rate in adults represent adaptations to facilitate communication during social behavior. (Session 38, Monday June 17, Cabildo, 10:30) AES – Samuel Gruber Award KEYWORDS: AMPULLAE OF LORENZINI, COMMUNICATION, ELECTRORECEPTION, FREQUENCY RESPONSE, RAJA EGLANTERIA

Skomal, G., and Chase, Bradford.
(GS) Massachusetts Shark Research Program, Mass. Div. Mar. Fish., Vineyard Haven, MA 02568-0068 USA; (BC) Cat Cove Marine Lab., Mass. Div. Mar. Fish., 92 Fort Ave., Salem, MA 01970 USA

The acute physiological effects of angling on post-release survivorship in blue sharks Prionace glauca

Extensive recreational fisheries for the blue shark, Prionace glauca, occur off the coast of Massachusetts from June through September every year. Tournament statistics show that 94% of all blue sharks caught annually are released by New England recreational fishermen. Since 1993, Massachusetts Division of Marine Fisheries biologists have been studying the acute physiological effects of angling induced stress on post-release survivorship of sharks, tunas, and billfish. Blood gases, pH, and serum constituents were measured in 55 blue sharks to characterize and quantify the acute physiological changes associated with high anaerobic muscular activity. Blue sharks were subjected to standard angling practices and sampled immediately by caudal venipuncture. Changes in blood pH, pCO2, pO2, acid-base status, and serum electrolyte, metabolite, and protein levels were quantified relative to fight time, gear type, hook location, and fish size. Post-release survivorship was evaluated with conventional and ultrasonic tagging. This species did not exhibit the profound changes in acid- base status and fluid homeostasis typically exhibited by tunas and marlin. Tag recaptures and short term sonic tracks of four blue sharks intentionally subjected to exhaustive exercise and blood sampling supports the notion that the physiological stress induced by angling does not compromise post- release survivorship in this species. (Session 18, Saturday June 15, Cabildo, 03:45) KEYWORDS: ANGLING, BLUE SHARKS

Sminkey, T.R.
(TS) FDEP, FMRI, 100 8th Av. SE, St. Petersburg, FL 33701-5020 USA

Demographic analyses of natural and exploited populations of three large coastal sharks

Concurrent with an increase in exploitation of sharks in the northwestern Atlantic, recent studies have documented the decline in abundance of three large coastal sharks: the dusky,Carcharhinus obscurus; the tiger, Galeocerdo cuvier; and the sand tiger, Odontaspis taurus. I used known and estimated life history parameters along with fishing mortality rates estimated in a recent stock assessment to estimate the potential effects of exploitation on the sharks’ population growth or decline. Fishing mortality levels (F=0.5, 0.10, 0.15, 0.20, or 0.25) were simulated to begin at an age corresponding to a mean carcass weight of 24 pounds. At F = 0.25 dusky, tiger, and sand tiger shark populations would decrease at rates of 15.0%, 10.4%, and 11.2% per year, respectively, and would decrease by one half in 4.3, 6.3, and 5.8 years. In the absence of fishing mortality, dusky, tiger, and sand tiger shark populations would increase at 5.6%, 10.4%, and 6.0% per year, respectively, and would double in 12.8, 7.0, and 12.0 years. Therefore, several decades without any exploitation will be required to rebuild these seriously depleted stocks. If any exploitation is maintained during rebuilding, stock recovery will take decades longer, and any other perturbation may have serious consequences. (Session 24, Sunday June 16, Cabildo, 09:30) KEYWORDS: DUSKY SHARK, TIGER SHARK, SAND TIGER SHARK, DEMOGRAPHY, EXPLOITATION

Stevens, J.
(JS) CSIRO Division of Fisheries; P.O. Box 1538; Hobart, Tasmania 7001; Australia

The productivity of Galeorhinus and the sustainability of the Australian fishery

The temperate triakid shark Galeorhinus galeus has been fished commercially in all parts of its range. In California, an intensive and rapidly expanding fishery for the liver oil of this species developed during the late 1930s and early 1940s. Catches declined from 2172 t in 1941 to 287 t in 1944 probably reflecting a collapse of the stocks which have apparently not fully recovered to this day. In Argentina and southern Brazil, a fishery developed rapidly during the 1990s and is now showing signs of stock collapse. Less intensive fisheries also occur in South Africa and off Europe. In southern Australia, the species has a long history of exploitation but despite concerns expressed since the 1950s the stock has not collapsed, although assessments put the current biomass at about 25% of virgin levels. Even among elasmobranchs, the productivity of Galeorhinus is low with a maximum longevity of about 60 years, late attainment of sexual maturity and a three year reproductive cycle. In addition to the management plan introduced in 1988, the survival of the stocks may have been aided by several factors including periods of unavailability to the demersal gear, a more complex spatial structure than originally thought and increased targeting of gummy shark. (Session 24, Sunday June 16, Cabildo, 08:15) KEYWORDS: GALEORHINUS, PRODUCTIVITY, SUSTAINABILITY, AUSTRALIAN FISHERY

Sundstroem, F., Reubush, K., and Gruber, S.
(FS, KR) Bimini Biological Field Station, University of Miami, Miami, FL 33149 USA; (SG) BBFS and Division of Biology and Living Resources, Rosenstiel School of Marine Science and Atmospheric Science, University of Miami, Miami, FL 33149 USA

Daily energy consumption of the lemon shark, Negaprion brevirostris: preliminary field determination

In an ongoing study in a tropical lagoon at Bimini, Bahamas, swimming speed as a measure of energy consumption and daily metabolic rate is being examined in sub- adult lemon sharks (Negaprion brevirostris). Energy consumption can be used to determine the impact of this apex predator on its environment. Each of 3 sharks was fitted with two ultrasonic transmitters. A 75 KHz coded identification transmitter was implanted in the celom and a 68 KHz speed-sensing transmitter was mounted at the base of the first dorsal fin. Three sharks (size: 188 cm, 170 cm, and 154 cm) have been manually tracked intermittently for periods between 1 and 15 days: The longest continuous track lasted forty hours. All tracks began immediately after surgery. Previous laboratory and field experiments have shown the average swimming speed of lemon sharks to be between 0.3-0.4 bodylengths per second. The initial data from this study agree with the published findings. Average burst speed recorded was 0.72 bodylengths per second during an average time of 7.4 seconds. A preliminary estimate of the average energy consumption of these lemon sharks was 440 Kj”d-1″. These results will be discussed in bioenergetic terms. (Session 11, Saturday June 15, Cabildo, 11:00) KEYWORDS: ENERGY CONSUMPTION, LEMON SHARK

Thomassen, L., and Gruber, S.
(LT) Boston University Marine Program, Marine Biological Laboratory, Woods Hole, MA 02543 USA; (SG) Rosenstiel School of Marine and Atmospheric Science, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149 USA

Tidal influences on the spatial distribution of lemon sharks, Negaprion brevirostris, in Bimini Lagoon, Bahamas

The spatial and temporal distributions of lemon sharks in Bimini lagoon were studied in relation to tidal changes in sea levels and currents. From June 1994 to September 1995, thirteen juvenile sharks (150-200 cm total length) were tracked using ultrasonic telemetry techniques. Changes in sea levels and currents were monitored at 10 stations across the lagoon over an eight month period. Such data allowed formulation of a time-dependent harmonic linkage to predictions for a NOAA reference station. Bivariate frequency distributions were used to analyze the associations of diel shark positions, individually and collectively, to coexisting tidal phases and sea level changes. Preliminary interpretation of plotted tracks reveal that these tide-related variables did influence the diel spatial distribution of lemon shark positions. (Session 04, Friday June 14, Cabildo, 01:45) AES – Samuel Gruber Award KEYWORDS: TIDE CYCLES, ULTRASONIC TELEMETRY,NEGAPRION BREVIROSTRIS

Villavicencio-Garayzar, C.
Laboratorio de Elasmobranquios, Depto. Biolog<i>a Marina, UABCS, A.P. 19-B. La Paz, B.C.S., México. CP 23080

Reproductive biology of the Pacific cownose, Rhinoptera steindachneri, in Baja California, México

Observations on specimens of the Pacific cownose, Rhinoptera steindachneri, from commercial captures were made from 1985 through 1995, in both coasts of the Baja California Pen<i>nsula. The Golfo de California is a zone of transit during the summer and autumm migration. Magdalena Bay, in the Pacific coast, is a puping and mating area from june through august. Maximum size in males and females were 96 and 108 cm disk width (DW), respectively. Maturity begin in males at 70 cm, and in females at 85 cm DW. Sex ratio in embryos, neonates and adults from both coasts were near two females for male. Only the left ovary and oviduct were functional, and just, one embryo per female was observed. Birth size is at 40-44 cm DW, after a gestation period of 10-11 months. (Session 18, Saturday June 15, Cabildo, 04:00) KEYWORDS: LA PAZ BAY, MAGDALENA BAY, RHINOPTERA STEINDACHNERI, REPRODUCTION

Walker, P., Howlett, G., Millner, R., van Leeuwen, P., and Daan, N.
(PW) NIOZ, P.O. Box 59, 1790 AB Den Burg, Texel, The Netherlands; (GH, RM) Ministry of Agriculture, Fisheries and Food, Fisheries Laboratory, Pakefield Road, Suffolk NR33 0HT, UK; (PvL, ND) Netherlands Institute for Fisheries Research, P.O. Box 68, 1970 AB IJmuiden, The Netherlands

The sensitive skate and fisheries – a North Sea perspective

Tag and return experiments on Raja species were carried out in the North Sea in the 1960’s and 1970’s and again between 1992 and 1995. During the first period more than three thousand rays were tagged, most of them in the western North Sea. Of these nearly 900 were returned, a 28% return rate. Prime species caught was the thornback ray, Raja clavata. In the 1990’s tagging was carried out across the North Sea. Nearly eight thousand rays were tagged and around 1200 were recaptured, a 16% return rate. Prime species caught was the starry ray Raja radiata. Dispersion parameters and mortality and growth rates were calculated for three species (R. clavataR. radiata and R. montagui) in both experimental periods. Reproductive strategies of these species were also studied during the past four years. Data on fecundity and length and age at maturity were collected. The data are analysed to address the hypothesis that the low dispersal capacity of rays makes them initially susceptible to local fisheries effects but that there are species-specific differences in sensitivity due to differences in life-histories. (Session 38, Monday June 17, Cabildo, 09:45) KEYWORDS: RAJA SPEC., DISPERSION, FISHERIES, FECUNDITY, MATURITY, NORTH SEA

Walsh, C.J., Luer, C.A., Bodine, A.B., Wyffels, J.T., Litman, G.W., Anderson, M.K., and Rast, J.P.
(CJW, CAL) Mote Marine Laboratory, Sarasota, FL 34236 USA; (ABB,JTW) ADVSc, Clemson University, Clemson, SC 29634 USA; (GWL,MKA,JPR) Department of Molecular Genetics, All Children’s Hospital, St. Petersburg, FL 33701 USA

The immune system of the clearnose skate, Raja eglanteria

Studies addressing immune function in sharks, skates, and rays are relatively rare, yet an understanding of elasmobranch immunology could provide valuable insight into the evolution of immunity. This presentation describes the current knowledge of cells and tissues comprising the immune system of a representative skate, the clearnose skate (Raja eglanteria). Major immune cell producing organs include the spleen, thymus, Leydig organ, and epigonal organ, with minor sites located in the intestine and peripheral circulation. Morphologically, immune cells of skates are similar to those of higher vertebrates, and include monocyte/macrophages, lymphocytes, and granulocytes. Functional identification of lymphocytes within immune cell producing tissues has been initiated using RNA in situ hybridization with probes specific for immunoglobulin (Ig) and T cell receptor (TCR) genes. These studies implicate spleen, Leydig organ, epigonal organ, and intestine in the production of lymphocytes expressing primarily Ig genes and thymus in the production of lymphocytes with primarily TCR genes. Preliminary studies are underway to explore mechanisms of graft rejection, typically a T lymphocyte-mediated response in higher animals. Additional functional characterization of cells isolated from skate immune tissues has involved investigation of phagocytosis with granulocytes from epigonal and Leydig organs demonstrating the greatest phagocytic activity. (Session 38, Monday June 17, Cabildo, 11:45) KEYWORDS: CLEARNOSE SKATE, RAJA EGLANTERIA, IMMUNE CELLS, IMMUNE FUNCTION

Wetherbee, B.M., Lowe, C.G., and Crow, G.L.
(BMW,CGL) Zoology Department University of Hawaii, Honolulu, HI 96822 USA USA; (GLC) Waikiki Aquarium, 2777 Kalakaua Ave., Honolulu, HI 96815 USA

Distribution, reproduction, and diet of the gray reef shark, Carcharhinus amblyrhynchos in Hawaii

Distribution, reproduction, and diet of the gray reef shark Carcharhinus amblyrhynchoswas examined using data collected during shark control programs in the main Hawaiian Islands (MHI) and during research fishing in the Northwestern Hawaiian Islands (NWHI). A total of 469 sharks was caught between 1967 and 1980. Gray reef sharks had a restricted distribution in the MHI, occurring only in the vicinity of Niihau and Molokini islands, but were one of the most abundant sharks throughout the NWHI. Catch rate was higher for males than for females in standard longline fishing at all locations and during all seasons. Depth distribution of males and females was similar, although females were more common at shallower depths. Males ranged in size from 79 to 185 cm total length (TL), and matured at between 120 and 140 cm TL. Females ranged in size between 63 and 183 cm TL and matured at about 120 cm TL. Litter size ranged from 3 to 6, with an average of 4.1 pups. Size at birth was estimated to be just over 60 cm TL. Most gray reef sharks (85%) consumed teleosts, but some sharks fed on cephalopods (29.5%), and crustaceans (4.9%). Larger sharks fed less frequently on teleosts and more frequently on cephalopods. (Session 18, Saturday June 15, Cabildo, 03:30) KEYWORDS: GRAY REEF SHARKS,CARCHARHINUS AMBLYRHYNCHOS, DISTRIBUTION, REPRODUCTION, DIET, HAWAII

Wilga, C., and Motta, P.
(CW, PM) Department of Biology, University of South Florida, Tampa, FL 33620 USA

Comparative functional morphology of upper jaw protrusion in Squaliform and Carcharhiniform sharks: a story of evolutionary and functional shifts

Squalus acanthias (Squaliformes) and Negaprion brevirostris (Carcharhiniformes) are both capable of protruding the upper jaw during feeding. Electromyography and high speed video reveal that the mechanism of upper jaw protrusion differs between the two sharks. The preorbitalis muscle pulls the upper jaw anteriorly in S. acanthias such that the long orbital processes slide ventrally in the ethmopalatine groove thus protruding the upper jaw ventrally. The levator palatoquadrati and the levator hyomandibularis muscles then act to retract the upper and lower jaws back under the cranium. In contrast, the levator palatoquadrati and the preorbitalis muscles pull the upper jaw anteriorly in N. brevirostris, sliding the short orbital processes anteroventrally through the ethmopalatine groove to protrude the upper jaw. The elastic ethmopalatine ligament passively retracts the upper jaw, while the levator hyomandibularis muscle acts to retract the hyomandibula and the posterior portion of the jaws. Because of their different cranial morphologies, the levator palatoquadrati muscle is dorsoventrally oriented in S. acanthias, and anteroventrally oriented in N. brevirostris. Therefore, through an evolutionary shift in the orientation of the levator palatoquadrati muscle from its ancestral dorsoventral orientation posterior to the orbit, to a more derived position anterior to the orbit, the function of the muscle has changed. (Poster Session 3, Monday June 17, Vieux Carre B, 27.) KEYWORDS: CARCHARHINIFORMES, SQUALIFORMES, UPPER JAW PROTRUSION, FEEDING, MUSCLE ACTIVITY PATTERNS, SQUALUS ACANTHIAS,NEGAPRION BREVIROSTRIS

Wyffels, J.T., Bodine, A.B., Mason, B., Bruels, M., Luer, C.A., and Walsh, C.J.
(JTW, ABB) Animal, Dairy and Veterinary Sciences Department, Clemson University, Clemson, SC 29634 USA; (BM, MB) Department of Medical Physics, Greenville Memorial Hospital, Greenville, SC 29605 USA; (CAL, CJW) Mote Marine Laboratory, Sarasota, FL 34236 USA

Acute effects of total body irradiation on juvenile clearnose skates, Raja eglanteria

Total body irradiation is a common technique for destruction of bone marrow in mammals. In order to characterize further the bone marrow equivalent in cartilaginous fishes the effects of radiation on the immune system were investigated. Clearnose skate, Raja eglanteria, eggs were shipped in aerated seawater, overnight express from Mote Marine Laboratory, Sarasota, Florida, to Clemson University, Clemson, South Carolina. The eggs were maintained in a 20#161#C recirculating seawater system. After hatch, animals were fed once daily. Approximately 14 weeks post-hatch the skates were transported to the radiation oncology department of a local research hospital and irradiated with 6MV x-rays from either a Varian Clinac 2300cd or 2100c linear accelerator. The skates received doses of 0, 1.5, 3, 4.5, 6, 9, 24, or 48 Gray. Twelve days post- irradiation, the skates were sacrificed by MS222 overdose. Morphometric data were collected and blood smears prepared. Partially dissected animals were immersed in 10% neutral buffered formalin. The fixed spleen and the epigonal organ with its associated gonads were weighed and later embedded in a plastic resin for semi-thin light microscopy. Blood differentials of animals from all treatments were compared. Although there were significant effects on organ weight, no radiation associated mortality was observed. (Session 44, Monday June 17, Cabildo, 01:30) AES – Samuel Gruber Award KEYWORDS: RAJA EGLANTERIA, IRRADIATION, SPLEEN, EPIGONAL, GONAD, BLOOD DIFFERENTIALS, HISTOLOGY

Yano, K., Goto, M., and Yabumoto, Y.
(KY) Seikai National Fisheries Research Institute, Ishigaki, Okinawa 907-04 Japan; (GM) Department of Anatomy, Tsurumi University, Tsurumi, Yokohama 230 Japan; (YY) Kitakyushu Museum and Institute of Natural History, Yahatahigashi, Kitakyushu 805 Japan

Dermal and mucous denticles of a female megamouth shark, Megachasma pelagios, from Hakata Bay, Japan

On 29 November 1994, a female megamouth shark, Megachasma pelagios, was stranded on the beach of northeast coast of Hakata Bay, Japan. This study presents a contribution to the morphology and histology of dermal and mucous denticles of several parts of the body of the female megamouth shark, 4710 mm in total length and 790 kg in body weight. In a scanning electron microscope studies, 25 skin and mucous membrane samples were collected after thawing. In histological studies, parts of the skin and mucous membrane samples were taken from the specimen. Decalcification in formic acid was followed by celloidin embedding and serial sectioning. Haematoxyline and eosin staining and Masson Goldner’s stain were used. The dermal and mucous denticles are very small, and differ in shape and size at each region of the body. The skin consists of outer epidermis layer which contains dermal denticles and inner dermis which is composed of dense fibrous tissue. The mucous membrane of the palate and tongue consists of an outer mucous epithelial membrane which contains mucous denticles, thin layer of lamina propia mucosae and thick layer of submucous tissue. The gill-raker is composed of the central cartilage and the mucous epithelial membrane which contains many mucous denticles. (Poster Session 2, Sunday June 16, Vieux Carre B, 04.) KEYWORDS: HAKATA BAY, MEGAMOUTH SHARK, MEGACHASMA PELAGIOS, DERMAL AND MUCOUS DENTICLES