Physiological responses in Eurasian perch ( Perca fluviatilis, L.) subjected to stress by transport and handling

Abstract

Eurasian perch ( Perca fluviatilis, L) were subjected to different stressors to determine the patterns of physiological response and recovery in this species. Fish were subjected to stress by transport and acute handling. In both studies, the temporal variation of the most important blood physiological parameters of primary and secondary stress responses was analyzed (for 3 weeks in transport study and for 24 h in handling experiment). Transport caused a slight decrease in serum osmolality for all the study except the 2nd day and a transient increase in haematocrit during the 2nd and 14th days. The most important response was a three-fold increase in cortisol levels (maximum value at 146 ng/ml) and a significant increase in glucose levels (1.5-fold) during the first week after transport, returning to basal levels during the following weeks. After acute handling stress, we observed immediate cortisol rise (peak of 121 ng/ml 2 h after stressor was applied), recovering to basal values 4 h after manipulation. We also found an increase in haematocrit values for all the study and in red blood cells number at 0.5 and 4 h after manipulation. Our results show that, as in other fish, the magnitude and duration of the physiological response are related to the stressor applied and that Eurasian perch shows a plasma cortisol response in the upper range and plasma lactate in the lower range compared to other species.