Exploring helicopter-vessel communication for mobulid bycatch avoidance in tropical tuna fisheries (Paper + presentation)
The incidental capture of non-target species (bycatch) in tuna fisheries is a threat to some marine vertebrates, including manta and devil rays (Mobulids). There is broad interest in reducing Mobulid bycatch in tuna fisheries; however, existing efforts mainly focus on reducing postcapture mortality rates. To explore a potentially novel pre-capture Mobulid bycatch avoidance and mitigation strategy, we conducted a small survey of tuna purse seine vessels’ helicopter pilots, spotters, and fishers operating in the eastern Pacific Ocean. We surveyed respondents on their ability to detect Mobulids prior to capture and their communication protocols with vessel crew. Results indicate that over half of the fishing crew searching for tuna from helicopters report being “always” or “sometimes” able to sight and identify Mobulids, and that helicopter crew regularly communicate Mobulid sightings to the vessel already. These results suggest that helicopter-vessel communication could be feasible for Mobulid bycatch detection, data collection, and potential avoidance, along with the associated potential improvements for science (e.g., data collection of observations). This study is the first to investigate the utility of helicopter-vessel communication as a bycatch mitigation strategy for elasmobranchs and identifies research and management directions that could be further investigated to avoid bycatch of Mobulids.