Diet of scalloped hammerhead shark in eastern Gulf of Mexico
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.
Complete Metadata
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| description | 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. |
| distribution |
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| identifier | gov.noaa.nmfs.inport:24913 |
| issued | 1998-01-01T00:00:00.000+00:00 |
| keyword |
[
"DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce",
"DOC/NOAA/NMFS/SEFSC > Southeast Fisheries Science Center, National Marine Fisheries Service, NOAA, U.S. Department of Commerce",
"EARTH SCIENCE > BIOLOGICAL CLASSIFICATION",
"EARTH SCIENCE > OCEANS > BATHYMETRY/SEAFLOOR TOPOGRAPHY > WATER DEPTH",
"EARTH SCIENCE > OCEANS > OCEAN TEMPERATURE > WATER TEMPERATURE",
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"OCEAN > ATLANTIC OCEAN > NORTH ATLANTIC OCEAN > GULF OF AMERICA",
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"163192",
"US DOC; NOAA; NMFS; Southeast Fisheries Science Center; Panama City, FL Laboratory",
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"STOMACH CONTENTS STOMACH CONTENTS - CONTENT WEIGHT",
"TAXONOMY",
"WATER TEMPERATURE",
"water depth",
"US DOC; NOAA; NMFS; Southeast Fisheries Science Center",
"Coastal Waters Of Florida",
"gulf of mexico",
"YSI - handheld multi-parameter instrument",
"scale",
"S. lewini",
"S. tiburo",
"diet",
"fishery-dependent",
"foraging ecology",
"resource partitioning",
"scalloped hammerhead sharks",
"1998-2005",
"Crooked Island Sound",
"St. Vincent Island",
"DOC/NOAA/NMFS/SEFSC > Southeast Fisheries Science Center, National Marine Fisheries Service, NOAA, U.S. Department of Commerce",
"A Comparison of the foraging ecology and bioenergetics of the early life-stages of two sympatric hammerhead sharks from 1998-07-12 to 2005-07-27 (NCEI Accession 0163192)"
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| language |
[]
|
| license | https://creativecommons.org/publicdomain/zero/1.0/ |
| modified | 2017-01-01T00:00:00.000+00:00 |
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"name": "Southeast Fisheries Science Center",
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"https://www.fisheries.noaa.gov/inportserve/waf/noaa/nmfs/sefsc/dmp/pdf/24913.pdf"
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|
| rights | otherRestrictions, unclassified |
| spatial | -85.087,29.652,-85.887,30.275 |
| temporal | 1998-01-01T00:00:00+00:00/2005-01-01T00:00:00+00:00 |
| title | Diet of scalloped hammerhead shark in eastern Gulf of Mexico |
