Potential of video techniques to monitor diversity, abundance and size of fish in studies of Marine Protected Areas

TLDR

Video techniques can be used for initial surveys and ongoing monitoring of Marine Protected Areas, offering cost‑effective, bias‑reduced, and widely accessible data collection beyond diver limits. The study reviews how single‑ and stereo‑video methods can assess fish community composition, abundance, and size, and explores baited remote video as a non‑intrusive, depth‑independent tool requiring robust sampling statistics. Authors describe using remote single‑ and stereo‑video systems—capable of operating beyond diver depth limits—to obtain precise fish morphometrics and abundance data, and discuss baited setups that provide depth‑independent, non‑intrusive monitoring.

Abstract

This paper briefly reviews applications of single-video and stereo-video techniques to help survey fish community composition and relative abundance, and fish length and weight. These techniques have potential application to the initial surveys of candidate habitats for Marine Protected Areas, and to the subsequent monitoring necessary to manage them. Remote video techniques can be used in shelf depths beyond the limits of diver-based Underwater Visual Census (UVC), and stereo-video systems can also be used to complement and enhance normal UVC by allowing very precise and accurate estimates of fish morphometrics (and hence weight). Some video techniques are very cost-effective and can help remove some major sources of observer bias in underwater observations, by removing the need for skilled observers in the field and by allowing simultaneous collection of a much wider suite of information in a permanent record that can be analysed later. This medium is directly accessible to an unlimited audience. Baited, remote video techniques offer a non-intrusive, depth-independent assessment tool with the advantages of both diver-based observation and capture techniques, but appropriate sampling statistics must be developed if relative abundance is to be measured adequately.