A field and video annotation guide for baited remote underwater stereo‐video surveys of demersal fish assemblages

Abstract

1. Baited remote underwater stereo-video systems (stereo-BRUVs) are a popular tool to sample demersal fish assemblages and gather data on their relative abundance and body size structure in a robust, cost-effective and non-invasive manner. Given the rapid uptake of the method, subtle differences have emerged in the way stereo-BRUVs are deployed and how the resulting imagery is annotated. These disparities limit the interoperability of datasets obtained across studies, preventing broadscale insights into the dynamics of ecological systems. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Tropicalization and kelp loss shift trophic composition and lead to more winners than losers in fish communities

“…We found evidence of that here with a mix of tropical and temperate fishes increasing and only temperate species showing a decline in occurrence. Although BRUVSs can underestimate richness and diversity metrics (Langlois et al, 2020; Stat et al, 2019; Watson et al, 2005), roving underwater visual censuses undertaken by divers in the Solitary Islands during 2001–2017 also reported strong increasing patterns of species richness for tropicalized mid‐shelf reefs (Malcolm & Ferrari, 2019).…”

“…BRUVS units consisted of video cameras attached to a metal frame and bait pole with a bait bag containing ~800 g of pilchard ( Sardinops neopilchardus ) 1.5 m in front of the cameras (Malcolm et al, 2007, 2010). The maximum number of individuals of a species in a single frame (MaxN) was recorded for each site and year using SeaGIS Event Measure software (http://seagis.com.au) as a conservative measure of relative abundance, as this method eliminates the chances of recounting the same fish (Harvey et al, 2012; Langlois et al, 2020). All adult fish within the field of view within an estimated 3 m of the camera were identified to species level where possible.…”

Analysis of fish population size distributions confirms cessation of fishing in marine protected areas

“…Importantly, our model does not require extensive, professionally-collected data on fish or fishers, as the inputs are simply a time series of fish numbers and sizes. With the increasing availability of inexpensive, video cameras configured in stereo, fish sizes can be readily and accurately surveyed by stakeholders or citizen scientists (Lowry, Folpp, Gregson, & Suthers, 2012), or potentially using less labor-intensive remote methods, such as remote operated vehicles (Perkins et al, 2020) or baited remote underwater video (Langlois et al, 2020). Elsewhere we have investigated the data requirements for our method, and discovered that unbiased estimates of harvest rates require observations of approximately 100 individuals per year for seven years (with fewer years possible if the size distribution is better characterized; Yamane, L., et al, unpublished manuscript).…”

Isolated reefs support stable fish communities with high abundances of regionally fished species

“…The relative abundance of regionally fished species at the Rowley Shoals was compared with five other remote reefs in the eastern Indian Ocean, which had been sampled using standardized BRUVS methodology (Langlois et al, 2020) (Meekan et al, 2006;Russell & Vail, 1988;Serventy, 1952). North Scott Reef has an enclosed lagoon surrounded by an outer reef flat and crest.…”