This manual relates to gear designed to acquire digital video imagery of macro-organisms living in the ocean’s water column, from small zooplankton (Letessier et al. 2013a) to marine mega-vertebrates (Letessier et al. 2014). A sister chapter on benthic BRUVs is included in the field package and addresses sampling protocols for demersal fish and shark assemblages (Chapter 5). The document aims to span everything from pre-survey planning to equipment preparation, field procedures, and on-board data acquisition to guarantee the efficient and correct use of pelagic BRUVs as monitoring tools in Australian Marine Parks (AMPs) and other Commonwealth waters. Such information is critical for supporting the development of consistent, concise, transparent and standardised guidelines in the collection and processing of pelagic BRUV data that can allow statistically robust comparisons between studies, sites, projects, and institutions.
Here, we consider both mono- and stereo-BRUVs7. While the latter can be calibrated to allow measurements of individuals’ body lengths and animal positions in three-dimensional space (Letessier et al. 2015), the former seems to remain a more prevalent approach in the literature due to lower costs and personnel/labour requirements (Whitmarsh et al. 2017). It is worth noting that other imagery-based methods such as mid-water towed video transects (Riegl et al. 2001), in-trawl cameras (Underwood et al. 2014), drop cameras (Friedlander et al. 2014), infrared thermography (Zitterbart et al. 2013), unmanned aerial vehicles (Kiszka et al. 2016), or diver operated videos (Goetze et al. 2015) are also available for monitoring pelagic environments and wildlife. These would each warrant a field manual in their own right (Mallet & Pelletier 2014), and are thus not included here (for further information, see Bouchet et al. 2017).
7 Mono-BRUVs consist of a single camera usually mounted directly behind or above the bait arm (Whitmarsh et al. 2017). Stereo-BRUVS consist of two cameras mounted at specific angles (ca. 7-8 degrees) either side of the bait arm.