Date of Award

2001

Degree Type

Thesis

Degree Name

Master of Science in Fisheries, Animal and Veterinary Science

Department

Fisheries, Animal and Veterinary Science

First Advisor

Conrad Recksiek

Abstract

A post release survivorship study of juvenile sandbar sharks (Carcharhinus plumbeus) was conducted in Delaware Bay during 1999-2000. A total of 104 sharks were captured and sampled for changes in blood chemistry after exposure to exhaustive exercise. Of these, 24 sharks were angled in the field, sampled, tagged, and released. The remaining 80 sharks were transported to a holding tank, allowed to recover, and half were angled to exhaustion. To quantify recovery, blood samples were taken from these fish at 0,1.5, 3, 6, 10, 14 and 24 hours, then tagged and released. Blood was obtained by caudal puncture and analyzed immediately for blood gasses and glucose. Serum samples were sent to a commercial laboratory for the determination of blood metabolites, proteins, and electrolytes. Blood levels of lactate, PCO2, glucose, K+, Ca2+, Mg2+, and CK were elevated following the stressor, while pH and HCO3- levels declined. Most metabolites returned to baseline within 6-10 hours. Moreover, 5 sharks were recaptured 0.03-12 months after release over the course of the study. These preliminary data indicate that sandbar sharks are able to physiologically recover after the exhaustive exercise associated with rod and reel angling and therefore, catch and release fishing may not severely impact neonatal and juvenile sandbar sharks in important nursery areas.

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