Improved Baited Remote Underwater Video (BRUV) for 24 h Real-Time Monitoring of Pelagic and Demersal Marine Species from the Epipelagic Zone

Abstract

Bait-based remote underwater video (BRUV) systems are effective devices for remotely observing fish and other marine organisms in challenging environments. The development of a long duration (24 h) surface BRUV observation surveys allowed the monitoring of scarce and elusive pelagic sharks and the direct impact on non-targeted species of longline fishing in the Western Mediterranean. Technological limitations, such as the limited storage capacity and a single surface camera, were improved by (i) adding a deep camera equipped with light (below 80 m depth) and (ii) replacing Gopros with a multi-camera video surveillance system (surface and depth) with a storage capacity of several days and access to real-time observation. Based on a deployment effort of 1884 h video data, we identified 11 blue sharks (Prionace glauca) and one bluntnose sixgill shark (Hexanchus griseus), a deep-sea species that scarcely swims at the surface. The real-time observation capability was a powerful tool for reducing logistical costs and for raising environmental awareness in educational and outreach programmes.

Preliminary Insights on the Habitat Use and Vertical Movements of Pelagic Stingray (Pteroplatytrygon violacea) in the Western Mediterranean Sea

“…The capture of one individual without a tail indicates that it could have been cut by the crew before being discarded, this practice has been mentioned in other fisheries [59]. Moreover, while sharks with residual hooks in the jaw are commonly observed [60,61], this has seemingly never been reported for pelagic stingray. This indicates that pelagic stingrays may be discarded with trailing gear, by cutting the branch line, which is not always close to the hook.…”

Preliminary Insights on the Habitat Use and Vertical Movements of the Pelagic Stingray (Pteroplatytrygon violacea) in the Western Mediterranean Sea

“…The capture of one individual without a tail indicates that it could have been cut by the crew before being discarded, this practice has been mentioned in other fisheries [62]. Moreover, while sharks with residual hooks in the jaw are commonly observed [63,64], this has seemingly never been reported for pelagic stingray. This suggests that pelagic stingrays may suffer mortality if they are discarded with trailing gear, by cutting the branch line which is not always close to the hook.…”

Studying Chondrichthyans Using Baited Remote Underwater Video Systems: A Review

“…This is certainly due to the large availability of these animals in the waters of these countries, but in the case of Australia, it is also due to the fact that it has demonstrated the potential of this tool in its waters for a long time [18,57]. In other parts of the world, such as the Mediterranean Region, where few studies have employed the use of BRUVS to study Chondrichthyans, it has only recently begun [41,78,89], the potential of this tool has yet to be recognized. BRUVS reduce labor costs and safety risks associated with deploying divers, and they provide extensive, high-resolution footage without physically disturbing marine habitats.…”