An integrated approach to tackling wildlife crime: Impact and lessons learned from the world's largest targeted manta ray fishery

Manta rays (Mobula birostris and M. alfredi) are threatened by overexploitation for international trade. Indonesia was home to the world's largest documented manta fishery-Lamakera, in East Nusa Tenggara. However, in 2014, the Indonesian government declared manta rays a protected species. Here we describe an integrated intervention to reduce manta hunting and mortality in Lamakera, which combined community outreach and livelihood-focused incentives with targeted enforcement actions; and assess its impact over a five-year period (2013-2018) using a theory-based research design. Results show that the intervention is associated with a significant decline in manta hunting effort and mortality (p < .001), which is correlated and temporally-associated with conservation activities, and did not occur for modeled and natural experiment counterfactuals. Overall, total manta ray mortality declined by 86% by 2018, vs. the 2013 baseline. We conclude that a multifaceted, data-driven approach reduced illegal hunting and trade of manta rays from 2013 to 2018. However, this impact is not indefinite; new challenges are emerging, which highlight the importance of a long-term adaptive strategy. We make several recommendations for designing interventions to mitigate trade-driven over-exploitation of megafauna: (a) understand diverse drivers of human behavior; (b) adopt data-driven problem-oriented planning; (c) continuously document and share learning; (d) establish partnerships with diverse stakeholders to develop resilient institutions for enduring impact.