PRIMARY AND SECONDARY STRESS RESPONSES IN GOLDEN PERCH, MACQUARIA-AMBIGUA

Golden perch (Macquaria ambigua), a species of Australian freshwater fish, were subjected to a number of simple stress procedures. Bloodsamples were taken and levels of commonly measured primary and secondary stress response parameters (cortisol, glucose and lactate) were determined. Anaesthesia and exertion of fish prior to bloodsampling affected resting levels of some of the parameters measured. Wild and aquarium-acclimated golden perch had low plasma cortisol levels (<2 ng/ml). Most fish appeared to adapt well to aquarium conditions, although occasional fish showed indications of being chronically stressed. Golden perch responded quickly to stress (<5 min), with increased plasma levels of cortisol and lactate. In contrast, glucose levels did not increase until at least 10 min after the stress was initiated; by 30 min, however, the typical hyperglycaemic response was observed. Golden perch recover rapidly from acute stress (<2.5 hr). Golden perch seem to acclimate quickly to conditions of chronic stress.