Accurate, rapid, and cost-effective fish assemblage monitoring is fundamental to marine protected areas (MPA) management as a pivotal tool to verify whether and t what extent MPA conservation objectives have been achieved and to redefine these objectives in the framework of an adaptive management. There has been a sharp increase in the number of video-based methods to study fish fauna, such as baited remote underwater video (BRUV) systems, that, depending on the objectives of the monitoring, can provide complementary or additional data to the more commonly used underwater visual census.

This study assessed the performance of a BRUV system in a Mediterranean MPA and to evaluate its effectiveness in assessing the structure of fish assemblages by comparing estimates with those obtained by the UVC technique. The fish fauna was monitored by BRUV and UVC in the Capo Caccia-Isola Piana MPA (Sardinia, Italy).

The results present 46 taxa and a total of 3620 individuals observed by BRUV, while 36 taxa and a total of 2995 individuals were observed by UVC. It is shown that the species first observed with the camera and able to reach the maximum abundance were the planktivores (Chromis chromis and Oblada melanura) followed by several carnivorous species belonging to the families Labridae, Serranidae and Sparidae, and lastly two carnivores (Mullus surmuletus and Mugilidae spp.) and some high-level predators (Dentex dentex, Seriola dumerilii, Sphyraena viridensis, Dicentrarchus labrax).

It is concluded that the consistency in findings between BRUV and UVC and a better performance of BRUV in detecting some species (mainly high-level predators), supports BRUV as an additional technique for describing and quantifying species richness and abundance also in the Mediterranean Sea. In addition, based on the results the advantages/disadvantages, shortcomings, suggestions and resources needed for the two techniques are outlined.

La Manna et al. (2021) Performance of a baited underwater video system vs. the underwater visual census technique in assessing the structure of fish assemblages in a Mediterranean marine protected area. Mediterranean Marine Science 22: 480-495.