A novel use of Stereo Baited Remote Underwater Video and Drop-Down Video for biodiversity and marine landscape mapping and prediction

PLOS ONE | https://doi.org/10.1371/journal.pone.0319355 April 3, 2025 6 / 23 PLOS ONE Marine landscape and biodiversity mapping using SBRUVs and DDV by the time of day of deployments, which were all conducted between 07:45 and 17:28 (all daylight hours), thus excluding any nocturnal sampling, as times for deployment were limited to boat availability and tides. Drop-Down Video (DDV) surveys were commissioned by Marine Scotland (now the Marine Directorate) with NatureScot, surveys were carried out in March and July 2013 aboard the Scottish Environmental Protection Agency (SEPA) research vessel MRV Sir John Murray (Table 2). In September of 2014 surveys were carried out onboard SEPA survey vessel [55]. Surveys in September 2018 were carried out using a fishing vessel [56] (Table 2). DDV cameras were used in accordance with recommending operating procedures as per JNCC guidelines [57,58], with camera high above the seabed maintained using laser measurements for consistency. Examination of the substratum was carried out for each SBRUV and DDV deployment, SBRUV frames were angled at ~ 15o oblique view to achieve a partial angle of the seabed as Table 2. Survey details from 2013–2019. All Stereo Baited Underwater Video (SBRUV) and drop-down video (DDV) surveys carried out between 2013–2019, including vessels used, camera equipment, depth, and times. Survey method Year Vessel Camera Equipment Min Depth (m) Max Depth (m) Earliest Start Time (HH:MM) Latest Start Time (HH:MM) SBRUV 2013 6.5 m RIB Canon HF G25 5 29.1 08:01 14:29 2014 RV Actinia 10.8 m Canon HF G25

4.1 47.2 07:52 14:44 2018 10.0 m creel boat Canon HF G25 5.82 45.9 08:47 16:25 2019 10.0 m creel boat Canon HF G25 5.49 40.7 08:51 16:27 DDV 2013 MRV Sir John Murray Kongsberg OE14–366 9.3 107.4 08:20 15:58 2014 RV Kelpie 7.9 m Outland SD camera 6 31 09:41 17:18 2018 Non-specialised fishing vessel C-Tecnics ST 3023 2 27 08:21 16:46 https://doi.org/10.1371/journal.pone.0319355.t002 Fig 3. Stereo baited remote underwater video setup ready for deployment. (A) bait box (B) W38VR Archon lights (C) underwater housings containing Canon HF G25 video cameras (D) float and ropes to deploy frame. https://doi.org/10.1371/journal.pone.0319355.g003