Can marine protected areas restore and conserve stock attributes of reef fishes?
Trexler, J.C.; Travis, J. (2000). Can marine protected areas restore and conserve stock attributes of reef fishes? Bull. Mar. Sci. 66(3): 853-873 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 |  |
| Abstract | One of the proposed benefits of marine protected areas (MPAs) is to conserve genetic diversity for life-history traits and to restore some semblance of the life history that was expressed before intense exploitation. Strong size-selective mortality from fishing has promoted an earlier age and smaller size at maturity in many species and a concomitant reduction in subsequent adult body sizes. These attributes are less economically desirable than those of fish from less heavily exploited stocks. We attempted to determine whether the establishment of marine protected areas, and the resulting relaxation of the directional selection produced by fishing mortality, would promote a substantial restoration of later ages at maturity. Our quantitative genetic models, calibrated with historical data from Gulf of Mexico populations of red snapper, Lutjanus campechanus, indicated that adequate variation should remain for life-history traits like age at maturity to respond to new fitness profiles. Marine species with planktonic larvae, including most economically important fishes, have high gene-flow rates that will preclude genetic differentiation between the no-take MPAs and the rest of the population. Any changes in the life history that are promoted by the no-take area may therefore ramify through the entire population. The establishment of no-take MPAs will promote substantial increases in the age at maturity if recruitment into them is not limited by density-dependent mortality. If it is, the benefit of no-take areas for increasing the age at maturity will be decreased. The no-take MPAs must serve as the major source of recruits for nearby fishing areas to produce the proposed benefits. The creation of MPAs will not replace the benefits of limiting age or size biases in harvesting by traditional fisheries management. |
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