Reproductive hormones: a tool for conservation

AWRUCH C. A.

Plymouth

Simposio; Annual Symposium of the Fisheries Society of British Isles. Symposium Theme: Biology, Ecology and Conservation of Elasmobranchs; 2015

Sharks are anevolutionarily conserve group that has survived for over 400 million years. Theirpermanence has largely depended on their reproductive strategies, as theprimary requirement for successful propagation of any species is the ability toreproduce. As in other vertebrates, reproduction in sharks is regulated via thehypothalamus?pituitary?gonadal (HPG) axis, where androgens and estrogens arethe main steroids during gonadal growth while progestins have maturationalactivity. In the last years, the declines in shark populations have called for thedevelopment of demographic models that address their vulnerability. Thesemodels include the size at which an animal sexually matures and the temporaland spatial patterns in reproduction. To obtain these parameters examination ofthe gonads after sacrificing the shark is required. However, for protectedspecies and bycatch species to be returned back into the water, destructivesampling is not allowed or is ethically inappropriate and should be minimised,yet there remains the need for scientific investigation. Consequently, inrecent years increasing studies showed that reproductive hormones have thepotential to be used as a non-lethal technique to address reproduction. However,although the use of reproductive endocrinology as a non-lethaltool is becoming crucial for the future of shark species, there are still majorgaps in understanding the HPG axis, and without a clear understanding on how thisaxis works mistakes could still be made in researchers? assumptions of thereproductive process. The aim of this review is assessing the use of sharkreproductive endocrinology as a basic-applied science for sustainable managementprograms.