LOWE, C.G.; TOPPING, D.T.; GALIMA, M.M.; GOLDMAN, K.J.; KELLEY, K.M.; Calif. State Univ., Long Beach; Calif. State Univ., Long Beach; Calif. State Univ., Long Beach; Jackson State Univ.; Calif. State Univ., Long Beach: Integrating physiological and behavioral responses of California sheephead exposed to fishing-related stressors and its implications towards management
Quantifying the effects of fishing-related stressors on nearshore gamefishes poses numerous challenges. We compared the physiological and behavioral response of California sheephead (Semicossyphus pulcher) caught on hook and line or rapidly sampled underwater to determine the effects of barotrauma. In both treatments, a small blood sample was taken from each fish to measure the level of cortisol (stress hormone), glucose, and lactate. Behavioral effects were determined by monitoring the rate of movement and area use using acoustic telemetry. Sheephead caught on hook & line were surgically fitted with small acoustic transmitters and followed over 24 hr period for up to 1 month. Some sheephead were fed acoustic transmitters hidden in squid and were followed until the fish regurgitated the transmitters. Fish blood sampled underwater showed no significant difference in cortisol levels between fish brought to the surface and rapidly blood sampled (< 3 min), but there was a difference in plasma glucose and lactate, which may be attributed to catecholamine release. Fish that fought against hook & line for > 3 min exhibited significantly higher plasma cortisol, glucose, and lactate levels. Fish caught on hook & line and tagged with acoustic transmitters showed slower rates of movement and covered less area in the first 6 hrs after release than fish fed transmitters underwater. These results suggest that sport angling of sheephead induces stress-associated alterations in both physiological and behavioral parameters. Ongoing studies are aimed at determining the time of physiological recovery in this economically important species. [Support by CA Sea Grant College Program NOAA NA06RG042 2001-02, project # R/F-192].
