Graduation Year

2020

Document Type

Thesis

Degree

M.S.

Degree Name

Master of Science (M.S.)

Degree Granting Department

Marine Science

Major Professor

Christopher Stallings, Ph.D.

Committee Member

Ernst Peebles, Ph.D.

Committee Member

Richard Cody, Ph.D.

Keywords

Discard Mortlaity, Recompression, Reef Fish, Venting, Survival

Abstract

In order to enhance the recovery of overfished stocks, fishery managers have implemented increasingly restrictive harvest regulations. However, discarded fish are susceptible to mortality from barotrauma when retrieved from depth. Venting tools are commonly used to enable fish to return to their depth of capture. An alternative method has been developed that involves the rapid descent of fish to their depth of capture to reduce buoyancy. In the Gulf of Mexico, the released portion of Red Snapper (Lutjanus campechanus) and Red Grouper (Epinephelus morio) has exceeded 80% of total catch. I tested the survival of these two economically important species after release using venting and recompression methods. Recapture rates for recompressed Red Snapper were higher than those from vented fish, indicating a lower discard mortality. While recompressing Red Snapper to at least 10 meters improved their survival rates over vented fish, recompressing them to 20 meters or deeper improved survival. The recapture rates for Red Grouper did not differ between release methods, possibly due to differences in physiology as well as how the fisheries operate and are managed between the two species. The combined results of this study indicate that there were species specific differences in the benefits of recompression, and this could assist fishery managers in providing guidance to anglers on where, when, and how and to use recompression devices more effectively.

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