BRUV’s consist of a GoPro that is mounted on a frame. 1 kg of standardized bait is placed in a wire cage mounted on a pole in the camera’s field of view. BRUV sampling is conducted throughout the Marine Park surrounding Nusa Penida. Locations of deployment for each site are chosen using a random number generator to avoid location bias and are placed in daylight hours..
The deployments are done in an area between 4m and 30m of depth, with a flat bottom to maximize line of sight. BRUV’s are deployed using SCUBA gear and diving lift bags to guide it away from live coral and to orient the BRUV facing down current. The BRUV is in the water for over 60 minutes and other activities (e.g training dives or survey dives) are simultaneously conducted no closer than 250m from the BRUV site.
At both the start and the end of each deployment environmental variable are measured including, water current speed, salinity, bottom depth, visibility and water temperature. Each video is viewed twice by a trained volunteer and data is recorded. Every elasmobranch or commercially valuable fish species present in the frame is counted and recorded.
Due to the difficulties of studying elasmobranch abundance in the wild, different techniques had to be invented in order to address different ecological questions. One of these techniques is the Baited Remote Underwater Video (BRUV). This shark study method has been used in numerous studies around the world and has been shown very successful.
The BRUV project is part of Dr. Mark Bond’s research to estimate and compare the relative abundance of predator fish species, including sharks and rays, inside and outside marine protected areas (MPAs). These species are also the most commercially valuable and play and important role in the local villages everyday life.
Several questions are waiting for an answer through this study: Is the correlation between diversity and relative abundance of elasmobranchs, and the size of the MPA? Are the MPAs created by NGOs and local villages being successful? Many people in the Gilis are not aware that the entire area is a protected marine park called Gili Matra Marine Natural Recreation Park.