This Archival Information Package (AIP) contains basic biological information on bonnethead and scalloped hammerhead sharks with specific (by stomach and prey item) diet information for these two species. Data were collected by the NMFS Southeast Fisheries Science Center; Panama City, FL Laboratory in the Northeast Gulf of Mexico and the Atlantic Ocean off the coast of Florida from 1998 to 2005. Data are in comma separated value (CSV) format and include length, sex, and number of prey items.

Juvenile scalloped hammerhead sharks, Sphyrna lewini, were collected in northwest Florida to examine foraging ecology, bioenergetics, and trophic level (30-60 cm FL mean FL 41.5 cm n 196). Diet analysis was performed using single and compound measures of prey quantity. Diet was also analyzed using seven broad diet categories (DC). Diet composition and estimated daily ration were compared to previously published information on bonnethead sharks, S. tiburo. Diet overlap was low between species. Juvenile S. lewini feed on relatively small (85 of prey items 5 shark length) teleosts (mostly bothids and sciaenids) and shrimps, whereas S. tiburo have been documented to feed mostly on crustaceans and plant material in northwest Florida. Plant material contributed little to the diet of S. lewini. Estimated daily ration was significantly lower for S. lewini (4.6 BW d-1) than for S. tiburo in northwest Florida, regardless if plant material was included in the model (p0.02 including and p0.00001 excluding plant material). Trophic level was calculated at 4.0 for S. lewini and 2.6 for S. tiburo. Stable isotope analysis showed S. lewini had significantly higher 15N values and significantly lower 13C values than S. tiburo, supporting the difference observed in calculated trophic level. These results provide evidence that small juvenile hammerhead species co-exist in coastal northwest Florida by feeding at separate trophic levels.

To examine variation in diet and daily ration of the bonnethead, Sphyrna tiburo (Linnaeus, 1758), sharks were collected from three areas in the eastern Gulf of Mexico: northwest Florida (29o40N, 85o13W), Anclote Key near Tampa Bay (28o10N, 82o42.5W), and Florida Bay (24o50N, 80o48W) from March through September, 1998-2000. In each area, diet was assessed by life stage (young-of-the year, juveniles, and adults) and quantified using five indices: percent by number (N), percent by weight (W), frequency of occurrence (O), index of relative importance expressed on a percent basis (IRI), and IRI based on diet category (IRIDC). Diet could not be assessed for young-of-the-year in Tampa Bay or Florida Bay owing to low sample size. Diet analysis showed an ontogenetic shift in northwest Florida. Young-of-the-year stomachs from northwest Florida (n68, 1 empty) contained a mix of seagrass and crustaceans while juvenile stomachs (n82, 0 empty) contained a mix of crabs and seagrass and adult stomachs (n39, 1 empty) contained almost exclusively crabs. Crabs made up the majority of both juvenile and adult diet in Tampa Bay (n79, 2 empty, and n88, 1 empty, respectively). Juvenile stomachs from Florida Bay (n72, 0 empty) contained seagrass and a mix of crustaceans while adult stomachs contained more shrimp and cephalopods (n82, 3 empty). Diets in northwest Florida and Tampa Bay were similar. The diet in Florida Bay was different from those in the other two areas, consisting of fewer crabs and more cephalopods and lobsters. Plant material was found in large quantities in all stomachs examined from all locations (15 IRIDC in 6 of the 7 life stage-area combinations, 30 IRIDC in 4 of the 7 combinations, and 62 IRIDC in young-of-the-year diet in northwest Florida). Using species- and area-specific inputs, a bioenergetic model was constructed to estimate daily ration. Models were constructed under two scenarios: assuming plant material was and was not part of the diet. Overall, daily ration was significantly different by sex, life stage, and region. The bioenergetic model predicted increasing daily ration with decreasing latitude and decreasing daily ration with ontogeny regardless of the inclusion or exclusion of plant material. These results provide evidence that bonnetheads continuously exposed to warmer temperatures have elevated metabolism and require additional energy consumption to maintain growth and reproduction.

Reproductive data from Atlantic sharpnose sharks were collected from specimens captured throughout the northern Gulf of Mexico on various research vessels. Data included those necessary to describe the size at maturity, reproductive cycle, mating period, gestation time and fecundity of the species.

A reassessment of the diet of the Atlantic sharpnose shark Rhizoprionodon terraenovae was conducted to provide an update on their trophic level (n390). Rhizoprionodon terraenovae primarily consume teleost fish however, loggerhead sea turtles Caretta caretta were also found in the diet for the first reported time. Analysis suggests that calculated trophic level may significantly depend on geographic area, thus adding a new factor to fishery management decisions.

This data contains morphology measurements of the Atlantic Sharpnose shark and stomach content analysis.

Atlantic sharpnose shark Rhizoprionodon terraenovae diet is described from Crooked Island Sound, an embayment of the northeast Gulf of Mexico. Diet was assessed by life-stage and quantified using six indices: percent by number, percent by weight, frequency of occurrence, the index of relative importance (IRI), IRI expressed on a percent basis (IRI), and IRI based on prey category (IRIPC). Young-of-the-year sharks (n56) fed on a mix of teleosts (mostly clupeids, 44.6 IRIPC) and invertebrates (combined, 25.1 IRIPC), juveniles (n185) on sciaenids (40.7 IRIPC) and clupeids (37.8 IRIPC), and adults (n105) on sciaenids (71.4 IRIPC). Differences in diet by site and ontogeny were tested by comparing diet from Crooked Island Sound with published information from St. Vincent Island in Apalachicola Bay, an adjacent estuary. Stomach contents were also used to expand on published prey size-predator size information.

The Gulf of Mexico Shark Pupping and Nursery (GULFSPAN) survey is a NOAA-led fishery-independent survey that examines the distribution and abundance of juvenile sharks in coastal areas of the Gulf of Mexico. The data describe coastal shark abundance, based on paired gillnet and longline surveys conducted monthly from April to October, and environmental data from Tampa Bay.

The Gulf of Mexico Shark Pupping and Nursery (GULFSPAN) survey is a fishery-independent survey that began in 1994 to examine the distribution and abundance of juvenile sharks in coastal areas of the Gulf of Mexico. The data describes coastal shark abundance and environmental data from St. Andrews Bay to Apalachicola Bay in the northeastern Gulf of Mexico.