1. Department of Agricultural and Resource Economics, University of California, Davis, Davis, CA 95616, USA
2. Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA
3. Woods Institute for the Environment, Stanford University, Stanford, CA 94305, USA
4. Marine Science Institute, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
5. Department of Biology, Stanford University, Stanford, CA 94305, USA
6. Department of Environmental Science and Policy, University of California, Davis, Davis, CA 95616, USA
7. Resources for the Future, Washington, DC 20036, USA