Contents lists available at ScienceDirect Biological Conservation journal homepage: www.elsevier.com/locate/biocon Evaluating the threat of IUU fishing to sea turtles in the Indian Ocean and Southeast Asia using expert elicitation Kimberly A. Riskas a, ⁎ , Renae C. Tobin a , Mariana M.P.B. Fuentes b , Mark Hamann a a College of Science and Engineering, James Cook University, Townsville, Australia b Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, USA ARTICLE INFO Keywords: Illegal fishing Wildlife trade Marine conservation Marine megafauna Marine turtle ABSTRACT Illegal, unreported and unregulated (IUU) fishing is a pervasive issue that affects economic, social, regulatory and environmental systems in all ocean basins. Research on the ecological impacts of IUU fishing has been relatively underrepresented, with minimal investigation into how IUU fishing may negatively affect populations of marine megafauna, such as sea turtles. To address this knowledge gap and identify priority areas for future research and management, we evaluated IUU fishing as a threat to a marine megafauna species group (sea turtles) in the Indian Ocean and Southeast Asia region (IOSEA). We designed and distributed an online survey to experts in the fields of sea turtle research, marine conservation, fisheries management, consulting and NGOs throughout IOSEA. Our results reveal that IUU fishing is likely to have potentially significant impacts on sea turtle populations in IOSEA through targeted exploitation and international wildlife trafficking. Addressing domestic IUU fishing needs to be actioned as a high priority within the study area, as does the issue of patrolling maritime borders to deter illegal cross-border transhipment. There is a demonstrable need to strengthen MCS and employ regional coordination to help build capacity in less-developed nations. Future research requirements include evaluating IUU fishing as a threat to sea turtles and other threatened marine species at multiple scales, further investigation into market forces throughout IOSEA, and examination of potential barriers to im- plementing management solutions. We advocate for introducing sea turtle-specific measures into IUU fishing mitigation strategies to help maximize the opportunity for positive outcomes in creating healthy ecosystems and stable communities. 1. Introduction Illegal, unreported and unregulated (IUU) fishing is a multifaceted regulatory issue that occurs in every ocean basin (Sumaila et al., 2006). The economic losses resulting from unlawful extraction of fisheries resources are believed to be substantial (Agnew et al., 2009; Nurhakim et al., 2008; WWF, 2016), and the drivers and loopholes that perpetuate IUU fishing are numerous and highly diverse (Flothmann et al., 2010; OECD, 2005; Schmidt, 2005). The environmental impacts of IUU fishing have been discussed as being similar to overfishing, concerning the depletion of target stocks (Pomeroy et al., 2007), changes in trophic dynamics following unsustainable harvest (Field et al., 2009), and ha- bitat damage caused by destructive fishing methods (McManus, 1997). IUU fishing includes a broad array of unlawful activities (Agnew et al., 2009), making it difficult to quantify empirically and frustrating efforts to assess the impacts of IUU fishing over spatial and temporal scales, as well as for different species. While it has been suggested that IUU fishing also has negative consequences for marine megafauna species, such as sea turtles (MRAG, 2005; OECD, 2005; UNODC, 2016), the subject has not yet been rig- orously investigated. To our knowledge, there has not been any specific assessment of IUU-related threats to sea turtles, despite numerous media reports of illegal sea turtle capture and trafficking by IUU fishing vessels (BOBLME, 2015). Indeed, alongside a growing awareness that criminal organizations are involved in the illegal harvest and trade of valuable fish species (Telesetsky, 2014; UNODC, 2011), Lindley and Techera (2017) observe that “less attention has been paid to the link between IUU fishing and organized crime” relative to trafficking of weapons, drugs and people. As such, the connection between IUU fishing and trafficking of marine wildlife such as sea turtles is one of interest from both a criminological and a conservation perspective. The Indian Ocean and Southeast Asia region (hereafter IOSEA) provides a highly suitable context for examining the linkages between IUU fishing and sea turtles. Reports of IUU fishing in the Indian Ocean include illegal longlining and turtle mortality in Mozambique (Louro et al., 2006), conflict over fishery access in Somalia (Beri, 2011) and https://doi.org/10.1016/j.biocon.2017.10.011 Received 19 January 2017; Received in revised form 4 September 2017; Accepted 9 October 2017 ⁎ Corresponding author at: 1 James Cook University Drive, Townsville City, QLD 4811, Australia. E-mail address: kimberly.riskas@my.jcu.edu.au (K.A. Riskas). Biological Conservation 217 (2018) 232–239 Available online 16 November 2017 0006-3207/ © 2017 Elsevier Ltd. All rights reserved. T