Assessing the effectiveness of a large marine protected area for reef shark conservation

Article history: Received 27 August 2016 Received in revised form 22 November 2016 Accepted 13 January 2017 Available online xxxx Large marine protected areas (MPAs) have recently been established throughout the world at an unprecedented pace, yet the value of these reserves formobile species conservation remains unclear. Reef shark populations continue to decline even within some of the largest MPAs, fueling unresolved debates over the ability of protected areas to aid mobile species that transit beyondMPA boundaries.We assessed the capacity of a large MPA to conserve grey reef sharks aNear Threatened specieswith awidespreaddistribution and poorly understood offshore movement patterns using a combination of conventional tags, satellite tags, and an emerging vessel tracking technology. We found that the 54,000 km U.S. Palmyra Atoll National Wildlife Refuge in the central Pacific Ocean provides substantial protection for grey reef sharks, as two-thirds of satellite-tracked sharks remained withinMPAboundaries for the entire study duration. Additionally, our analysis of N0.5million satellite detections of commercial fishing vessels identified virtually no fishing effort within the refuge and significant effort beyond the MPA perimeter, suggesting that large MPAs can effectively benefit reef sharks and other mobile species if properly enforced. However, our results also highlight limitations of place-based conservation as some of these reef-associated sharks moved surprising distances into pelagic waters (up to 926 km from Palmyra Atoll, 810 km beyond MPA boundaries). Small-scale fishermen operating beyond MPA boundaries (up to 366 km from Palmyra) captured 2% of sharks that were initially tagged at Palmyra, indicating that large MPAs provide substantial, though incomplete, protection for reef sharks. © 2017 Elsevier Ltd. All rights reserved.