Exploring practical conservation measures for pelagic thresher sharks using local knowledge in Sunda Banda Seascape

Rafid Arifuddin Shidqi ^1,2* Yodhikson Marvelous Bang ² Samsul Basrun ² Dewi Ratna Sari ² Maria Bernadeth Tukan ² Hollie Booth ³

• ¹ Nicholas School of the Environment, Duke University, Durham, North Carolina, United States
• ² Thresher Shark Indonesia, Kalabahi, Nusa Tenggara Timur, Indonesia
• ³ University of Oxford, Oxford, England, United Kingdom

The pelagic thresher shark (Alopias pelagicus) is an evolutionary distinct and globally endangered species, with population declines primarily attributed to targeted-and by-catch in small-scale and industrial fisheries. As the world's largest shark fishing nation, Indonesia is a global priority for thresher shark conservation, and recent studies revealed that the Sunda Banda seascape in eastern Indonesia is a hotspot and migration route for this species. Many fisheries also operate in this seascape, likely posing a threat to thresher sharks. However, there is a lack of data on fisheries interactions with thresher sharks in the area, which hinders efforts to mitigate overfishing and promote conservation. This study addresses this gap by drawing on local ecological knowledge from fishers in Banda, Central Maluku, Indonesia. We used mixed methods approach combining surveys (N=52) and focus group discussions (N=25), with fishers were selected via purposive and snowball sampling. This allowed us to explore Banda fishers' socio-economic attributes, knowledge of, attitudes, and interactions regarding pelagic thresher sharks and their conservation. Our results identified 16 locations where fishers captured or sighted pelagic threshers, all overlapping with Ay-Rhun and Banda Sea Marine Protected Areas. We found that fishers primarily depended on fishing for their livelihoods, with some having previously participated in shark fisheries and trade. However, pelagic thresher sharks are not a targeted species due to their low economic value. Instead, they are accidentally caught in small-scale handlines and purse seine fisheries associated with fish-aggregating devices. The meat is consumed or sold locally as a cheap source of animal protein, particularly during periods of less fish catch. Fishers highlighted the costs of thresher shark bycatch, such as increased costs to repair broken nets. This suggests that win-win approaches, such as an incentive-based intervention to encourage bycatch release, are feasible to resolve this conservation problem.