TRACKING GLOBAL FISHERIES FROM SPACE: PATTERNS, PROBLEMS, AND PROTECTED AREAS

Abstract

Fishing is one of the largest and most widespread ocean uses affecting marine ecosystems and biodiversity. From small-scale coastal vessels to industrialized high-seas fleets, the footprint of modern fisheries extends over much of the global ocean. Nonetheless, we have only limited understanding when, where, and how those fisheries are occurring, especially in remote areas far from shore. This poses a problem for fisheries management efforts and marine conservation measures such as marine protected areas (MPAs), which are being established to meet global conservation targets. Fishing is an important factor influencing the effectiveness of MPAs. It is therefore of vital importance to map and analyze the global footprint of fisheries and better understand its influences on the efficacy of marine conservation measures and fisheries management. I apply a novel satellite-based monitoring tool, the Automatic Identification System (AIS), to analyze behavior and movement patterns of fishing vessels globally in the context of marine conservation. For this I developed methods to automatically analyze fishing effort from AIS data and applied these to analyze patterns of fishing vessel behavior around the globe. These new tools allowed me to describe the global distribution of fisheries at fine spatial and temporal resolution. In some cases, fishing effort accumulated close to the boundaries of MPAs, an indicator of spillover of fish benefiting fishing fleets nearby. Near the Galápagos Marine Reserve, fishing effort within 20 km from the reserve boundary was four times higher than in the surrounding area, and tuna catches were higher and more stable near the reserve boundary as well. Patterns of fishing effort around 12 other large MPAs were shaped predominantly by their proximity to Exclusive Economic Zone and MPA boundaries, showing the major effects of maritime zoning regulations on fishing effort. Furthermore, fishing was increased around older MPAs and those in developing countries. Linking fishing vessel behavior to seafood supply chains, I also documented global patterns and hot spots of transshipment of catch to cargo vessels. Using AIS data I found transshipment particularly important in high seas fisheries, such as tuna longlining, raising concerns about mixing of legal and illegal catches in some of the world’s most widespread and valuable fisheries. Finally, I reviewed the effectiveness of spatial protection for highly migratory fish, which is related to a range of species characteristics (e.g. migration, aggregation and homing behaviors) as well as management features (fleet dynamics and management effectiveness). These results provide deeper insight into the global behavior of fishing vessels and highlight the potential and applicability of AIS vessel tracking data to document fishing and transshipment activities in unprecedented detail. By opening a new window of transparency to remote ocean areas, this work provides a foundation for improved high seas governance and management of marine living resources, especially in waters beyond national jurisdiction.