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dc.contributor.advisorStunz, Gregory W.
dc.contributor.authorTompkins, Alex K.
dc.date.accessioned2018-02-05T20:24:10Z
dc.date.available2018-02-05T20:24:10Z
dc.date.issued2017-08
dc.identifier.urihttp://hdl.handle.net/1969.6/19197
dc.description.abstractReducing discard mortality in Gulf of Mexico (GOM) Red Snapper Lutjanus campechanus remains an important parameter for stock rebuilding. Red Snapper discard mortality remains high due to barotrauma injury sustained during capture and high catch rates, but recent development of fish descender devices can mitigate these declines. To estimate discard mortality rates associated with descender devices, Red Snapper were captured from the bottom via hook-and-line methods and released with descender devices across a depth gradient of 30 to 80 m. At each depth, fish were randomly assigned to three release treatment groups: one-third of their capture depth, two-thirds of their capture depth, and release at the seafloor. A subset of fish from each release treatment were tagged with ultrasonic acoustic transmitters to estimate short-term survival. The fate of released fish was classified using a combination of visual observation, acoustic profiles, and underwater video footage. Results showed strong depth effects, with the odds of survival decreasing by 50% with every 10 m increase in capture depth. Survival was independent of the depth at which descender devices released fish, suggesting that rapid recompression even to shallow depths will reduce discard mortality. Underwater video footage of descended fish revealed substantial depredation may occur, and was greater with increasing depth. Barotrauma impairment reached a maximum around 55 meters and decreased thereafter, resulting in seemingly less impaired fish at greater depths, despite low survival. In addition to rigorous field experimentation, the perceptions, opinions, and attitudes of over 500 recreational anglers were surveyed regarding the use of descender devices in the GOM and South Atlantic recreational Red Snapper fishery. Over 1,100 free descender devices were distributed to recreational anglers from North Carolina to Texas. After using the devices during a normal fishing season, recipients completed a survey assessing their perceptions of the devices. While 72% of respondents had little to no knowledge of the devices prior to the study, 70% changed their preferred release method from venting to descending. Anglers released over 7,000 Red Snapper and 4,000 other reef fish species with descender devices during this study, and 76% were likely to continue employing the devices on their vessel. Eighty-nine percent of respondents believed descending Red Snapper would significantly reduce discard mortality in Red Snapper. These findings help achieve better calculations of overall mortality, and provide managers with information on how descender devices may improve survival of discarded Red Snapper. The key finding was recreational anglers perceive descender devices to be highly useful in reducing discard mortality and are willing to employ the devices when releasing reef fish experiencing barotrauma.en_US
dc.format.extent101 pagesen_US
dc.language.isoen_USen_US
dc.rightsThis material is made available for use in research, teaching, and private study, pursuant to U.S. Copyright law. The user assumes full responsibility for any use of the materials, including but not limited to, infringement of copyright and publication rights of reproduced materials. Any materials used should be fully credited with its source. All rights are reserved and retained regardless of current or future development or laws that may apply to fair use standards. Permission for publication of this material, in part or in full, must be secured with the author and/or publisher.en_US
dc.subjectbarotraumaen_US
dc.subjectdescender deviceen_US
dc.subjectdiscard mortalityen_US
dc.subjectrapid recompressionen_US
dc.subjectred snapperen_US
dc.titleUtility of rapid compression devices in the Gulf of Mexico red snapper fisheryen_US
dc.typeTexten_US
thesis.degree.disciplineMarine Biologyen_US
thesis.degree.grantorTexas A & M University--Corpus Christien_US
thesis.degree.levelMastersen_US
thesis.degree.nameMaster of Scienceen_US
dc.contributor.committeeMemberCurtis, Judson M.
dc.contributor.committeeMemberYoskowitz, David W.
dc.description.departmentLife Sciencesen_US
dc.description.collegeCollege of Science and Engineeringen_US
dc.type.genreThesisen_US


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