Recent research projects

The abbreviation BRUVS stands for Baited Remote Underwater Video System. For the past 15 years, these have been used to record the presence of marine life (fishes in particular) using video cameras. Their main appeal is that they can be left in place (either on the seabed or suspended in open water) for a set period of time, recording the marine life which is in the immediate vicinity or which might be attracted to them from some distance away (typically when the system is baited). They were developed in the late 2000s, utilising the development of mini video cameras, which have proved popular with outdoor sports enthusiasts.

Three BRUVS units were used in an experimental survey to investigate fish diversity within the MPA during the Marine Festival in the summer of 2022. The units were kindly lent for this project by the Blue Marine Foundation, having been constructed a few years earlier by staff at the University of Sussex.

Essentially, a BRUVS unit consists of a metallic frame designed to provide a stable platform for mounting the mini video cameras. A 1 m long rod extending horizontally from the frame supports a bait basket at its far end, which is filled with a bait (typically mashed-up fish) suitable for attracting meat-eating fishes. By mounting two video cameras on the frame either side of this rod and aimed at the bait basket, a stereo image can be generated which, when processed with appropriate software, can provide the lengths of fishes in the cameras’ field of view (this analysis has yet to be done on the recordings made at Lundy in 2022).

Two deployments of the three BRUVS frames took place on two days during August 2022, producing 12 video records in total. Each deployment was at a different depth (between 6.9 and 21.8 m below chart datum), on a different seabed habitat and at a different location around the island. Each recording lasted for an hour’s duration.

The fishes which were ‘caught’ by the cameras fell into two groups: (1) those that were attracted by the bait; and (2) those that seemed oblivious to the bait but just happened to be in the area, possibly attracted to the disturbance to the seabed of the frame.

The first category were all species of sharks: smooth hound Mustelus mustelus; nursehound or bull huss Scyliorhinus stellaris; and small-spotted catshark Scyliorhinus canicula. All of these species are scavengers, tending to consume dead, dying or wounded fishes or, on occasion, shellfish. This is why they were attracted to the bait of mashed-up mackerel. Edited highlights showing the shark species mentioned above can be seen here.

The second category included species frequently encountered by divers when they are either close to the seabed (such as various species of wrasse and the conger eel) or in open water (such as pollack). These species are not scavengers. Adult pollack will feed mostly on other (live) fish such as sand eels and members of the cod or herring families; wrasse species will feed on amphipods, other small crustaceans, worms and small molluscs; and conger eels mostly feed on live fishes or crustaceans at night.

A total of 13 species of fishes were recorded by the BRUVS, together with a number of other scavenging invertebrate species including common lobster Homarus gammarus, spiny lobster Palinurus elephas, spiny spider crab Maja brachydactyla and spiny starfish Marthasterias glacialis.

Robert Irving's 2022 report on the NTZ studies undertaken during the Marine Festival includes this BRUVS study, is listed in the Bibliography and can be found here.