Gamefish populations in North America are experiencing increasingly elevated recreational fishing pressures; however, the impacts of current fishing regulations have not been evaluated for most marine species. Mandatory catch and release often results from size and bag limits with the assumption of fish survival and recovery with minimal sublethal effects. Depending on the intensity and duration of the stressor, acute stress from angling and handling can have deleterious physiological and behavioral impacts with consequences for fish health and fitness. We evaluated the short-term sublethal effects of angling-related stressors on kelp bass, Paralabrax clathratus, one of the most popular gamefish in southern California. Collaborating with recreational anglers to capture fish using standard hook and line practices, we evaluated biochemical responses and recovery by collecting blood samples at different time points after capture (10-120 min), after fish were released and some were recaptured (3h to 186 d). Blood cortisol, glucose, and lactate were significantly elevated and steadily increased in the hour following capture and holding (p < 0.001). Fish caught, released, and recaptured after varying time at liberty were found to have returned to basal levels in < 24 h (p > 0.05). Physiological stress responses were positively correlated with angling and handling duration, but negatively correlated with increasing fish size (p < 0.05), suggesting that larger individuals may be more resilient to capture stress. Likewise, kelp bass exhibited no signs of cumulative or chronic stress from repetitive angling/recapture events and recovered to basal levels in <24 h (p > 0.05). Kelp bass were also tagged with acoustic accelerometer transmitters and tracked to evaluate fine-scale behavioral effects of angling stress on their normal diel movement and activity. Reduced frequency of high acceleration movements (i.e. rapid feeding strikes) was observed for 33 h post-release, followed by recovery and evidence of elevated feeding behavioral activity. Rate of movement and area use size showed high individual and temporal variation; however, reduced movement immediately after release steady increased to normal levels over the first 10 h post-release. There was no discernable effect of angling on area use size, but areas of high relief substratum may be important refuge habitat for angled kelp bass during recovery. By integrating physiological and behavioral endpoints for kelp bass to standard angling induced stress we conclude that this species is able to recover in <24 h; however, smaller individuals may be more susceptible to predation during this recovery period. Based on these findings, it is likely that kelp bass may still fair well under current size and bag limits.
|Advisor:||Lowe, Chris G.|
|Commitee:||Harris, Michael, Johnson, Darren|
|School:||California State University, Long Beach|
|School Location:||United States -- California|
|Source:||MAI 58/01M(E), Masters Abstracts International|
|Subjects:||Biology, Ecology, Aquatic sciences|
|Keywords:||Angling, Catch and release, Fisheries, Kelp bass, Physiology, Stress|
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