A Time-Extended (24 h) Baited Remote Underwater Video (BRUV) for Monitoring Pelagic and Nocturnal Marine Species

Agusti Torres,Ana-Maria Abril,Eric E G Clua

doi:10.3390/jmse8030208

Abstract

Baited remote underwater video systems (BRUVs) are efficient devices for remotely characterising the assemblage and relative density of fishes and other marine organisms. However, technological constraints (e.g., battery life and limited storage memory) typically limit deployment times to <2 h making it very difficult to capture the presence of marine species, including rare and elusive ones. We developed an extended duration (24 h) BRUV to enable fisheries-independent surveying of a pelagic shark population in the western Mediterranean. Video data revealed seven visits (three nocturnal, four diurnal) by blue sharks (Prionace glauca) over a period of 1355 h. In the future, this cost-effective device could be fitted with a wireless video transmitter to provide real-time observations of marine animals for scientific or ecotourism purposes.

Highlights

Thanks to advances in digital camera and battery technologies, the use of baited remote underwater video systems (BRUVs) has increased since initial deployments in the 1990s [1,2]
We developed an extended duration (24 h) Baited remote underwater video systems (BRUVs) to enable fisheries-independent surveying of a pelagic shark population in the western Mediterranean
Despite relatively high device cost and labor-intensive video data analysis [3], BRUVs have been widely used in studies characterising species diversity and abundance of fishes

Summary

Introduction

Thanks to advances in digital camera and battery technologies, the use of baited remote underwater video systems (BRUVs) has increased since initial deployments in the 1990s [1,2]. Despite relatively high device cost and labor-intensive video data analysis [3], BRUVs have been widely used in studies characterising species diversity and abundance of fishes (see review by [4]). BRUVs could potentially provide an effective fisheries-independent method of monitoring diminished shark populations, but only if recording times can be increased significantly beyond current norms in order to effectively sample low shark densities. The duration of video sampling in the Finprint project [10] is 60–90 min which may be too short to document sharks in locations where their populations have been heavily diminished by fishing.

Study Site and Sampling Effort

Method for Shark Attraction and Video Recording

Findings

F Length estimate