Evaluating stress in sharks using biochemical methods

AWRUCH C. A.; SIMPFENDORFER, C.; PANKHURST, N. W

Congreso; 8th Indo-pacific Fish Conference; 2009

Indo-pacific Fish Conference

Collecting, handling and holding sharks before release can have significant effects on fish physiology and survival, however the study of stress, including post-release mortality for sharks is very limited. Sharks are important components of Queensland’s East Coast Inshore Finfish Fishery (Australia) where there is already a high level of release of sharks by Queensland recreational fishers. Despite increasing rates of release of sharks there is no information on their fate after release. To assess the post-release mortality, sharks were captured in a hook line, and blood samples were collected in couplets: at time 0 (capture) then 3 mins, 0 and 10 mins, 0 and 30 mins and 0 and 60 mins. Lactate values were tested using “in situ” lactate kit and plasma concentrations of the stress hormone 1á-hydroxicorticosterone and corticosterone were measured by Thin Layer Chromatography (TLC) and radioimmunoassay (RIA). During capture and release, the condition of these sharks was recorded. We determined if measurable levels of 1á-hydroxicorticosterone and corticosterone were present in different species of sharks including the variability in hormone levels between species and between individuals within a species. Secondly, we correlated 1á-hydroxicorticosterone and corticosterone levels with lactate values of the shark during capture and release to determine the degree of variability in this stress hormone and the relationship being found between this hormone and different levels of stress.