"The grainy fisheries management of the Silky Shark, a genetic perspective" скачать в хорошем качестве

"The grainy fisheries management of the Silky Shark, a genetic perspective"

Presented by Derek Kraft (ToBo Lab - Hawaiʻi Institute of Marine Biology). Sharks who roam the open ocean are difficult to manage. Long-distance movements between seemingly endless blue water, across international boundaries, and lack of dispersal data make it difficult to define management units (stocks). These stock boundaries are essential for any successful wildlife management, and boy do pelagic sharks need it. The silky shark in particular is the second most caught shark on the planet. Their habitat happens to overlap with the commercial tuna fishing grounds across the sea and silky sharks make up over 90% of shark bycatch in these industries. Additionally, there are intentional shark fisheries harvesting silky sharks to sell their fins in the shark fin industry. Due to this heavy fishing pressure, their numbers have collapsed by over 85% in the past 20 years. We used advanced genetic techniques to examine silky shark DNA from across the globe to outline population boundaries. We found several discrete populations within areas once thought to be one single population. These results call for a change in management units if we hope to conserve this shark species.