As 2017 gets underway, CEI welcomes a whole host of new interns and research technicians across the institute. With the start of the spring semester, the bull shark (Carcharhinus leucas) tagging project enters its fourth year. The shark team began the year with the capture of a 265cm total length female in the Cape Eleuthera Marina. On the 25th of January, the team used the poly ball method to hook and draw the shark to the research vessel for data collection. A satellite tag and an internal acoustic tag were installed and various measurements and tissue samples were collected. These tags will relay location data to CEI, which will then be used to assess habitat use among multiple spatial scales in order to uncover patterns in residency and associations with specific environments.
Sharks are highly threatened, with overall populations now less than 10% of what they were before the industrial revolution. Sources of the decline include the finning industry as well as bycatch in various commercial fisheries. The bull shark specifically, is classified as near threatened by the IUCN, therefore a better understanding of its habitat association is essential for successful conservation legislation. One of the greatest challenges regarding the conservation of such a large, highly mobile fish is that protection laws substantially differ between countries and jurisdictions. While these sharks are protected in Bahamian waters, we are hoping to develop more comprehensive frameworks for the protection of this, and other species of shark that are threatened.
The CEI Elasmobranch Research and Conservation Program has now tracked eight female bull sharks in an attempt to discern patterns in this species’ habitat use. CEI hope to tag more individuals in the upcoming months to better inform conservation management. By tracking the location of these sharks, the research team can determine any trends in the movement as the bull sharks leave thesanctuary of the Bahamian waters and use this data to encourage protective legislation in other areas.
After these females leave Cape Eleuthera around April, we will expect to see the same individuals (and typically a few new females) back in October later this year. You can follow more updates regarding this and our other exciting research on Facebook and Instagram.