Diet of bonnethead shark in eastern Gulf of Mexico

Description

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.

Resources

Name Format Description Link
0 View the complete metadata record on InPort for more information about this dataset. https://www.fisheries.noaa.gov/inport/item/24912
33 NOAA Data Management Plan for this record on InPort. https://www.fisheries.noaa.gov/inportserve/waf/noaa/nmfs/sefsc/dmp/pdf/24912.pdf
0 View the complete metadata record on InPort for more information about this dataset. https://www.fisheries.noaa.gov/inport/item/24912
0 The information provided on this page seeks to define how the GCMD Keywords are structured, used and accessed. It also provides information on how users can participate in the further development of the keywords. https://www.earthdata.nasa.gov/learn/find-data/idn/gcmd-keywords
33 NOAA Data Management Plan for this record on InPort. https://www.fisheries.noaa.gov/inportserve/waf/noaa/nmfs/sefsc/dmp/pdf/24912.pdf
0 Global Change Master Directory (GCMD). 2024. GCMD Keywords, Version 19. Greenbelt, MD: Earth Science Data and Information System, Earth Science Projects Division, Goddard Space Flight Center (GSFC), National Aeronautics and Space Administration (NASA). URL (GCMD Keyword Forum Page): https://forum.earthdata.nasa.gov/app.php/tag/GCMD+Keywords https://forum.earthdata.nasa.gov/app.php/tag/GCMD%2BKeywords

Tags

  • ysi - handheld multi-parameter instrumentysi - handheld multi-parameter instrument
  • coastal waters of florida
  • fishery-dependent
  • 0163192
  • 1998-2005
  • biological data
  • ruler
  • oceans
  • water temperature
  • stomach contents - content weight
  • stomach contents - prey taxonomy
  • panama city
  • noaa
  • southeast fisheries science center
  • tampa bay
  • nmfs
  • biological classification
  • ocean temperature
  • oceanography
  • us doc
  • doc/noaa/nmfs/sefsc
  • measuring board
  • gulf of mexico
  • u.s. department of commerce
  • earth science
  • national marine fisheries service
  • bathymetry/seafloor topography
  • 163192
  • diet
  • biological
  • fl laboratory
  • anclote key
  • florida bay
  • stomach contents - prey count
  • water depth
  • animals - individual - stomach contents
  • laboratory analyses
  • bonnethead
  • young-of-the-year
  • north atlantic ocean
  • scale
  • a comparison of the foraging ecology and bioenergetics of the early life-stages of two sympatric ham
  • stomach contents
  • depth sounder

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