Clustering of disaggregated fisheries data reveals functional longline fleets across the Pacific

Contributors: Timothy H. Frawley, Barbara A. Muhling, Heather Welch, Katherine L. Seto, Shui-Kai Chang, Francisco Blaha, Quentin Hanich, Myeonghwa Jung, Elliott L. Hazen, Michael G. Jacox, Stephanie Brodie

Organizations: Institute of Marine Science, University of California Santa Cruz, Santa Cruz, CA • Environmental Research Division, NOAA Southwest Fisheries Science Center, Monterey, CA • Fisheries Resources Division, NOAA Southwest Fisheries Science Center, La Jolla, CA • Department of Environmental Studies, University of California Santa Cruz, Santa Cruz, CA • Graduate Institute of Marine Affairs, National Sun Yat-sen University, Kaohsiung, Taiwan • Independent Fisheries Advisor, Waiheke Island, New Zealand/Aotearoa • Australian National Centre for Ocean Resources and Security (ANCORS), University of Wollongong, Wollongong, NSW, Australia • Fisheries Policy Research Division, Korea Maritime Institute, Busan, Korea • Physical Sciences Laboratory, NOAA Earth System Research Laboratories, Boulder, CO

Summary: Ensuring the long-term sustainability of tuna, billfish, and other transboundary fisheries resources begins with data on the status of stocks, as well as information concerning who catches what fish, when, where, and how. Despite recent improvements in fisheries monitoring and surveillance, such dynamics remain poorly understood across the high seas. Here we delineate and describe pelagic longline activity in the Pacific Ocean using a framework that integrates descriptive vessel information and tracking data with species- specific catch reports. When parsed by distinct vessel behaviors and attributes, disaggregated fisheries data highlight the existence of multi-national, multi-specific (i.e., targeting multiple species) fishing fleets, many of which target waters that span more than one management area. Our findings emphasize the need for increased coordination across regional and sub-regional governance bodies and suggest that effective and equitable management of the sector may require efforts to move beyond single-species, single-area controls and operational distinctions based primarily on vessel flag and/or gear type alone.