Trade-offs between fish habitat and fishing mortality and the role of reserves
Mangel, M. (2000). Trade-offs between fish habitat and fishing mortality and the role of reserves. Bull. Mar. Sci. 66(3): 663-674
In: Bulletin of Marine Science. University of Miami Press: Coral Gables. ISSN 0007-4977; e-ISSN 1553-6955, more
Also appears in:Coleman, F.C.; Travis, J.; Thistle, A.B. (Ed.) (2000). Essential fish habitat and marine reserves: Proceedings of the 2nd William R. and Lenore Mote International Symposium in Fisheries Ecology, November 4-6, 1998, Sarasota, Florida. Bulletin of Marine Science, 66(3). Rosenstiel School of Marine and Atmospheric Sciences: Miami. 525-1009 pp., more
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| Abstract |
Ludwig (1995) argued that (1) management for sustained yield cannot be optimal and (2) effective management models cannot be realistic. I concur, and I begin with the view that sustained yield is more important than maximum yield; indeed maximum sustained yield must become a constraint rather than a target. Mangel et al. (1996) stress that we are very far from managing ecosystems; we manage human interventions in ecosystems. Following Ludwig's advice, I will use a relatively simple model to show how essential fish habitat and fishing mortality are intimately connected -loss of spawning habitat is equivalent to additional fishing mortality on adults. Reserves can help guarantee sustainability of the fishery, even when fishing mortality outside the reserve cannot be very well controlled (despite attempts to do so). In fact, in some circumstances (identified by the model) reserves can simultaneously enhance the stock, protect habitat, and increase catch. Finally, I will show how the model can be used to help resolve the reserve design question, which in this case is how we decide how much spawning habitat and how much of the fishing ground to protect. |
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