Investigating the potential of helicopter-vessel communication for bycatch avoidance in tuna purse seine fisheries

Background/Question/Methods

The unintentional capture of non-target species (bycatch) in industrial fisheries impacts long-lived species, including manta and devil rays (collectively Mobulids), dolphins, sea turtles, and sharks. These species are particularly vulnerable to bycatch due to their life-history traits, including delayed maturity and low fecundity. Though some industrial fisheries have implemented policies to mitigate these declines, there is a need to develop additional bycatch mitigation strategies to reduce their mortalities. Including fishers’ knowledge in these efforts can help to guide the development of effective conservation actions. Fleet-wide communication programs, in which vessels share information on interactions with bycatch species in real-time, is one way in which the involvement of fishers has helped address bycatch and may be a useful inclusion to mitigation strategies. Given previous conservation gains from fleet-wide communication, we investigate whether vessel-helicopter communication has the potential to help avoid bycatch. We surveyed helicopter pilots, spotters, and fishers working in the tuna purse seine fishery in the EPO to understand and identify visual perceptions of bycatch species prior to capture as well as their communication with the vessel. Questions were based on four components: participant demographics, indicators used to sight species, visual identification of species, and communication with the vessel.

Results/Conclusions

Quantitative analysis of survey results revealed demographic differences among survey answers, such as how occupation or experience affects participants’ abilities to identify non-target species. Responses to species-specific questions were compared to determine differences in helicopter pilots’ and fishermen’s abilities to sight different non-target species. Qualitative analysis revealed emerging themes among responses, such as specific species’ characteristics that make them recognizable. Preliminary results suggest that visual identification of non-target species is possible prior to capture and could be a feasible bycatch avoidance measure. Helicopter-vessel communication can be particularly useful when large groups of non-target species are encountered, for instance when mobulids gather and feed in large aggregations. Communication between tuna helicopter pilots and their associated vessels about where non-target species are located could advance potential bycatch avoidance strategies in large and impactful fisheries and at the same time help to fill knowledge gaps about the ecology of the most vulnerable species.