Interactions of tuna fisheries with the Galapagos marine reserve

The largest protected areas of any kind have all recently been established in the ocean. Since 2012, 5 protected areas that exceed 1 million km(2) in size have been created, mostly in remote oceanic areas. The potential conservation and fisheries benefits of such reserves have been debated in the public, the media, and the scientific literature. Little is known about their effectiveness for commercially valuable pelagic predators, especially for highly migratory species such as tuna and billfishes. Here we analyse the iconic Galapagos Marine Reserve, documenting interactions with and changes in associated tuna purse seine fisheries in the Eastern Tropical Pacific. Using a combination of long-term onboard ob server data and a novel data set of high-resolution, remotely sensed vessel tracks (Automatic Identification System [AIS]), we reveal progressive divergence of tuna fishing effort, catch, and catch per unit of effort (CPUE) trends in areas adjacent to the reserve from trends in the surrounding fished areas. Both data sets show a regionally unique hotspot of concentrated effort along the western reserve boundary now receiving >4-fold greater fishing effort density than the rest of the surrounding area. These dynamic interactions of tuna purse seine fisheries with the Galapagos Marine Reserve suggest that the reserve might enhance fish stock availability to local fisheries and help to stabilize local catches despite overall decreasing biomass trends for these highly commercial tuna stocks.