Sampling strategies should be designed to ensure valid inferences and interpretations of resulting data (Smith, Anderson & Pawley 2017). We recommend spatially balanced statistical routines, such as R package MBHdesign (Foster et al. 2019), which can incorporate environmental information and legacy sites to create sampling designs with known inclusion probabilities (Foster et al. 2017, 2018). Due to the need to revisit each site to retrieve stereo-BRUVs after deployment, spatially balanced designs may be inefficient for sampling large regions (>10 minutes transit time between samples), and clustered sampling designs may be preferred (Hill et al. 2018).
Individual stereo-BRUV samples should be separated to reduce the likelihood of non-independence due to individuals being concurrently sampled by adjacent stereo-BRUVs. Separation distance will depend on the mobility of the species and the habitat being studied, for typical demersal fish assemblages a minimum of 400 m for one-hour deployments is recommended (Bond et al. 2018b) or 250 m for 30 minute deployments (Cappo, Speare & Wassenberg 2001).