Combining acoustics and accelerometry data to assess killer whale interactions with longline fisheries in south-eastern Australia

Marine Courtois

    The current increased competition for space and resources between humans and animals resulted in a global amplification of Human-Wildlife Conflict often source of substantial social, economic, and ecological consequences in both terrestrial and marine environments. Due to a limited amount of data available, depredation interactions between marine mammals and fisheries are likely to be greatly underestimated, exacerbating impacts on local fishing industries. The present study focused on the extent of killer whale (Orcinus orca) depredation on blue-eye trevalla (Hyperoglyphe antarctica) longline fisheries in south-eastern Australia. A combination of accelerometry and acoustic data was used for the first time to assess the level of interaction in the area and to gather information on the spatio-temporal pattern of captures of the target species. The findings of this study suggested that detection rate might be largely underestimated in longline fisheries when assessed with surface observations only. Killer whales were repeatedly found to be present on-site outside of fishing operations and/or capture events time and a high level of depredation on blue-eye trevallas was recorded. The study provided primary recommendations for fisheries management on how to adapt fishing practices to potentially minimize depredation interactions while maintaining the profitability of the local industry.