Costs and benefits of towed videos and remotely operated vehicles for sampling shallow reef habitats and fish

Where several different tools are available for research, the costs and benefits associated with each option become an important part of the selection process. Towed video (ToV) and remotely operated vehicles (ROVs) are both widely used to assess shallow reef benthic habitats and fish assemblages, but quantitative data on their comparative performance is limited. The relative abilities of commercially available ToV and ROV were assessed using two low-cost (less than A$10 000), manually deployable systems. These systems were deployed to collect photographs of marine habitats and videos of fish assemblages along six 200-m transects at three separate sites. The time required to operate each system and the specific limitations and advantages of each system were compared. Both systems performed equally in terms of the resolution of data collected on benthic habitats and fish assemblages on shallow reefs. However, ToV required significantly less time (∼60% less) to collect data than ROV, and should allow cost savings with no loss in data quality. We recommend ToV as a cost-effective and easily deployable system for assessing rocky reef habitats and fish assemblages.