Understanding and reducing the impact of fishing on discarded sharks and rays with innovative new tools for conservation and research

key aim of applied marine conservation research is to understand and manage the impact of human activities on marine biodiversity. Sharks and rays (elasmobranchs) form an important component of marine systems and they provide important ecosystem services. However, declines in elasmobranch populations are being documented in fisheries around the world. We are still developing an understanding of the full impacts of fishing on elasmobranchs and many of the effects of fisheries discards on their populations are still unresolved. Little consideration has been given to the potentially pervasive effects of capture-induced parturition (premature birth or abortion) on elasmobranch populations. Capture-induced parturition is an issue faced by elasmobranchs caught as bycatch in fisheries targeting other species. Bycatch and discarding is of concern for a number of fishing methods, but this thesis focuses on gill-net fisheries. More specifically those gill-nets deployed extensively in a number of countries as a strategy to cull sharks for the protection and safety of bathers. Managers have few options to reduce this bycatch and there are few socially accepted or proven alternative methods to mitigate shark incidents. I aimed to address these knowledge gaps by using a variety of methods and by pioneering new techniques...