COS 94-3 - Modelling and mapping fishing pressure and fish standing stocks across Micronesian coral reefs, and assessing the potential impacts of climate change

Friday, August 12, 2016: 8:40 AM
124/125, Ft Lauderdale Convention Center
Alastair R. Harborne1, Alison Green2, Nate Peterson2, Maria Beger3, Peter Houk4, Mark Spalding2, Brett Taylor5, Eric Treml6, Laurent Vigliola7, Ivor D. Williams8, Nicholas Wolff2, Philine zu Ermgassen9 and Peter J. Mumby10, (1)Department of Biological Sciences, Florida International University, North Miami, FL, (2)TNC, (3)ARC Centre of Excellence for Environmental Decisions, The University of Queensland, St. Lucia, Australia, (4)University of Guam, (5)NMFS/PIFSC/FRMD, (6)University of Queensland, (7)IRD New Caledonia, (8)Coral Reef Ecosystem Division, NOAA Pacific Islands Fisheries Science Center, Honolulu, HI, (9)Global Marine Team/Department of Zoology, The Nature Conservancy and University of Cambridge, Cambridge, England, (10)The University of Queensland, St Lucia, Australia
Background/Question/Methods

Marine ecosystem goods and services, such as protein provision, are being affected by a range of anthropogenic stressors, and maintaining their integrity represents an important goal of conservation and management. For example, coral reef fisheries are vital to Micronesian economies, but may be overexploited. As part of The Nature Conservancy’s Mapping Ocean Wealth project, we assembled a database of 1127 fish surveys across five jurisdictions of Micronesia (the Republic of Palau, the Federated States of Micronesia, the Territory of Guam, the Commonwealth of the Northern Marianas, and the Republic of the Marshall Islands) to model and map fishing pressure and current standing stocks. A GIS of 22 potential predictor variables, including human population size, distance to markets, and oceanic temperature and productivity, were used to model fishing pressure and current and potential standing stock at a 1 ha resolution across the study area.

Results/Conclusions

Using mean parrotfish size as an indicator of fishing pressure and controlling for biophysical gradients, we demonstrate that fishing is best predicted by distance to the nearest port and human population pressure within 200 km. This metric of fishing pressure and biophysical variables were then used to model standing stock. Standing stock increased with increasing oceanic productivity, upstream larval supply, depth, and coral cover, and decreased with increasing sea surface temperature and fishing pressure. The models were then used to predict fishing pressure and current standing stock across all reefs in the study area, providing the first continuous maps of these variables for Micronesia. Furthermore, we mapped potential gains in standing stock that might be obtained in no-take reserves by simulating zero fishing pressure. The ratio of current to potential standing stock also generated spatially explicit estimates of fisheries status and potential time to recovery. Finally, the models also provide insights into the impacts of rising sea surface temperatures that are expected to alter fish distributions and reduce body size. These maps and models are important regional resources to inform policy and aid protected area design and fisheries management.