Baited Remote Underwater Video Stations (BRUVS) have been developed by AIMS scientists in order to monitor the vast areas of deeper inter-reef and shelf habitats inaccessible to research divers so that important bioregions there can be included in marine protected areas.
BRUVS consist of tourist-grade "HandiCam" video cameras in simple underwater housings made of PVC sewer pipe and acrylic, with a canister of minced pilchards on the end of a bait arm in the field of view. The housings are held in steel frames, and are deployed in strings of four to six under separate ropes and floats, to be picked up after one or two hours filming at the seabed.
Baited videos record species attracted to the bait plume or camera station, species attracted to the commotion caused by feeding and aggregation at the station, species occupying territories within the field of view of the camera, and species indifferent to the station but present in or passing through the field of view during the deployment.
BRUVS confer several advantages over traditional sampling and underwater visual census methodologies for surveying fish community composition and relative abundance:
- They can be used at depths beyond the safe limits of research diving.
- They are non-destructive so they can be used where extractive sampling is prohibited.
- They are non-intrusive so they can capture large, mobile animals, such as sharks and rays, which would avoid scuba divers.
- The give a permanent record that can be closely examined by scientists around the world for identification and shown to managers and fishermen alike for their own interpretation.
- They give precise length and biomass estimates when used in stereo-pairs with analysis software.
- They remove observer bias.
- They give a detailed image of the habitat types in the sampling area.
The range of fish, sharks, rays, sea snakes and other animals sighted on BRUVS tapes has been remarkable – over 300 species to date, from 3cm leatherjackets to 3m hammerhead sharks.
BRUVS have been used by AIMS to compare shark populations at Scott Reef with an unfished Commonwealth marine reserve. BRUVS revealed a marked difference in the abundance of sharks at Scott Reef and the protected area. The number of sightings in the video recordings indicated that sharks were on average 4-17 times more abundant in the reserve. This result was reinforced when the time it took for sharks to appear in each video was analysed and on Scott Reef was on average twice that in the reserve.
Over 1,600 BRUVS sets were also deployed throughout the entire GBRMP as one of the survey tools in the "seafloor biodiversity project". Striking cross-shelf and bioregional patterns in communities of fish, sharks, rays and sea snakes were identified in that study.