DOE aims to catch sharks on camera for BRUV research project

Mar 12, 2018 News

Shark researchers from the Department of Environment are deploying remote underwater cameras around all three islands for its the biannual BRUV shark study. BRUV stands for baited, remote, underwater video, and it is used to calculate a relative abundance of sharks in our waters. The DOE and volunteer field workers place underwater cameras on a particular stretch of reef. The cameras have an arm that extends a few feet in front of the lens with a bag of bait on the end to attract predators. Any sharks that show up to investigate are caught on camera. Department of Environment shark project officer Johanna Kohler and volunteer field workers deploy one of four baited remote underwater video cameras on Grand Cayman's north wall. "We are using it as one of our methods to study them, we don't have to go down there, we don't interfere with their usual life, we just have this camera down there with a bait attached," said Ms. Kohler. A small pouch of chopped makerel is attached to the BRUV unit to attract sharks and other predators, but Ms. Kohler told Cayman 27 it's not meant to be a free meal. "The object is not to feed the fish or the predators, it is just to create a plume to attract them into the field of view of the camera, and then we can look at the footage later and do our statistical analysis on it," said Ms. Kohler. The BRUVs record everything that happens for two hours, at which point, they are retrieved. "We do this twice a year, we do it once in March and April and once in October, November," said Ms. Kohler. Ms. Kohler told Cayman 27 while specific population numbers have yet to be established, the BRUV survey has helped the DOE's understanding of these apex predators. "We have learned which species occupy switch habitat, we have learned what kind of species are around here, what kind of shark species, we have learned approximately where they hang out, around each island and between the islands," said Ms. Kohler She says the BRUV study enhances the DOE's other avenues of shark research. "We continue to learn," explained Ms. Kohler. "This is an ongoing study, an ongoing monitoring tool that the DOE uses to study are shark population in Cayman." Monday's trip out to the north wall with four BRUV units netted the shark project more than eight hours of raw footage. Ms. Kohler told Cayman 27 the DOE and project partner Marine Conservation International go through every frame of the footage, and catalog the various species that appear. This allows them to calculate the relative abundance of sharks. Once the BRUV survey is complete in Grand Cayman, the project will move on to the sister islands.