Abstract
Fish are commonly released following capture in recreational and commercial fisheries, based on regulatory considerations or ethical angling. Understanding physical and physiological consequences of capture techniques can help determine the odds of post-release survival and help to design strategies to mitigate adverse effects. Similarly, for fish caught, tagged and released for research purposes, minimizing the impact of capture is a priority to ensure rapid return to normal behavior. Physical impacts of hooking in different locations and barotrauma in fish brought up from deep water, are commonly assessed,1,2 as have physiologic effects of various methods of capture3. The black sea bass (Centropristis striata) is a marine fish common along the east coast of the United States in shallow near-shore waters to depths of >100 m. It is popular in both recreational and commercial fisheries. We compared blood gases, pH and lactate values of black sea bass collected by hook and line or by fish trap, from shallow (7.5 m) or deeper (38 m) water, using an iStat point of care analyzer. We hypothesized that physiologic impacts would be greater for fish caught by hook and line, and for fish captured from greater depth. Groups were compared by Kruskal-Wallis one-way analysis of variance with a Wilcoxon rank sums each pairs post hoc test. Significant differences among groups were detected in pH, pCO2 and lactate. Blood pH was lower in the deep trap group than the deep hook and line and the shallow trap groups (with shallow hook and line intermediate). Blood pCO2 was higher in the deep trap and shallow hook and line groups than in the shallow trap and deep hook and line groups. Blood lactate concentration was greater in the deep trap group than both hook and line groups and greater in the shallow trap group than the shallow hook and line group. Changes were interpreted as mild respiratory acidosis in the deep trap and shallow hook and line group, and mild to moderate lactic acidosis in the trap groups. Physiologic effects of hook and line capture were less than expected, possibly because of rapid retrieval with minimal opportunity to resist.
Acknowledgements
We thank Jacob Krause, Brendan Runde, Jeffrey Buckel, and Sarah Cannizzo for technical assistance. The Patricia McClellan-Green Summer Scholars Program provided partial funding for C. Pelletier.
*Presenting author
Literature Cited
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2. Rudershausen PJ, Buckel JA, Hightower JE. 2014. Estimating reef fish discard mortality using surface and bottom tagging: effects of hook injury and barotrauma. Can J Fisheries Aquat Sci. 71:514–520.
3. Skomal GB. 2007. Evaluating the physiological and physical consequences of capture on post-release survivorship in large pelagic fishes. Fisheries Manage Ecol. 14:81–89.