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Getting hooked: a study to better understand sea turtle longline by catch
Title
Getting hooked: a study to better understand sea turtle longline by catch.
Creator
Warraich, Natasha, Wyneken, Jeanette, Graduate College
Abstract/Description
Loggerhead and leatherback sea turtles are often caught as longline bycatch in fisheries worldwide. These species of sea turtle differ greatly in life history, morphology, and the ways they are hooked. Leatherbacks tend to be “foul hooked,” externally in the shoulder or flippers, while loggerheads tend to be hooked in the mouth or they swallow the bait so that hooking is internal esophagus or stomach. The numbers of loggerheads and leatherbacks caught decreased after changes in gear, bait and...
Show moreLoggerhead and leatherback sea turtles are often caught as longline bycatch in fisheries worldwide. These species of sea turtle differ greatly in life history, morphology, and the ways they are hooked. Leatherbacks tend to be “foul hooked,” externally in the shoulder or flippers, while loggerheads tend to be hooked in the mouth or they swallow the bait so that hooking is internal esophagus or stomach. The numbers of loggerheads and leatherbacks caught decreased after changes in gear, bait and time of sets. However the proportion of leatherback mouth hookings increased while foul hooking decreased. We described and compared prey approach and attack behavior of both species in the presence and absence of visual targets. Waterborne squid and jellyfish odors were used to elicit feeding behavior in the two species. Visual targets were necessary to elicit biting. Loggerheads approach their prey with the mouth wide open, have exceptionally good aim and usually bite their intended target. This accuracy is consistent with the mouth and internal hooking. Leatherbacks frequently overshoot, miss their intended target then have to re-approach the target multiple times before making contact. Leatherback feeding behavior is disrupted easily if the body or flippers are touched during prey approach. This reapproach behavior may make leatherbacks more prone snagging on lines rigged with J-hooks. The shift by some fisheries to circle hooks, which are less prone to snagging, by give the leatherbacks multiple chances to attack the bait and ingest it without getting hooked externally.
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Date Issued
2014
PURL
http://purl.flvc.org/fau/fd/FA00005861
Format
Document (PDF)
Feeding behavior of loggerhead (caretta caretta) and leatherback (dermochelys coriacea) sea turtles: a model to understand bycatch
Title
Feeding behavior of loggerhead (caretta caretta) and leatherback (dermochelys coriacea) sea turtles: a model to understand bycatch.
Creator
Warraich, Natasha, Wyneken, Jeanette, Graduate College
Date Issued
2013-04-12
PURL
http://purl.flvc.org/fcla/dt/3361369
Subject Headings
Leatherback turtle, Loggerhead turtle, Feeding behavior in animals, Bycatches (Fisheries)
Format
Document (PDF)
Feeding behavior of loggerhead and leatherback sea turtles:a study to better understand longline bycatch
Title
Feeding behavior of loggerhead and leatherback sea turtles:a study to better understand longline bycatch.
Creator
Warraich, Natasha, Wyneken, Jeanette, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description
Two species of sea turtle, loggerheads (Caretta caretta) and leatherbacks (Dermochelys coriacea) are caught frequently as bycatch in longline fisheries. These fisheries use hooks baited with fish or squid. Yet, leatherbacks feed on gelatinous prey while loggerheads are carnivores. I investigated the responses of these two species to bait odors in controlled laboratory experiments to better understand their feeding behavior and why they interact with longlines. Both species initiated feeding...
Show moreTwo species of sea turtle, loggerheads (Caretta caretta) and leatherbacks (Dermochelys coriacea) are caught frequently as bycatch in longline fisheries. These fisheries use hooks baited with fish or squid. Yet, leatherbacks feed on gelatinous prey while loggerheads are carnivores. I investigated the responses of these two species to bait odors in controlled laboratory experiments to better understand their feeding behavior and why they interact with longlines. Both species initiated feeding behavior in the presence of squid bait odors and just C. caretta showed feeding behavior with sardine odors; neither responded to mackerel odors. The turtles are hooked differently on longlines. Loggerheads are usually hooked in the mouth while leatherbacks are usually hooked in the shoulder or flippers. Comparisons of prey attack behavior and accuracy in apprehending a stimulus in the presence of waterborne food odors identified speciesspecific differences that may predispose the turtles to particular kinds of hooking.
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Date Issued
2014
PURL
http://purl.flvc.org/fau/fd/FA00004171, http://purl.flvc.org/fau/fd/FA00004171
Subject Headings
Bycatches (Fisheries) -- Prevention, Longlining (Fisheries) -- Bycatches -- Prevention, Longlining (Fisheries) -- Environmental aspects, Sea turtles -- Effect of fishing on, Sea turtles -- Habitat -- Conservation, Sea turtles -- Mortality, Wildlife conservation
Format
Document (PDF)