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Marine Reserves have also been shown to facilitate the recovery of severely damaged ecosystems. For instance, large sections of Georges Bank off the coast of Massachusetts were closed to fishing in 1995. Hermen, Collie, and Valentine (2003) began noting "steady and marked increase...in production" within just a few years after the closure. As a matter of fact, the improved survival rates rate of the 1995 year class of cod on Georges Bank was noted as the primary source of increased biomass for the four year period following the closures (Canadian Department of Fisheries and Oceans 1999). In general, signs of recovery can appear quickly, sometimes within 2-5 years of the establishment of a No-Take Area, and tend to persist for as long as protection remains in effect (Gell & Roberts 2003).
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In addition, Marine Reserves provide significant value for scientific research by being a control against which outside changes can be compared. This can greatly alleviate one of the historic problems of ecological science, : the difficulty in interpreting results from the "experimental" areas that have been disturbed by human activities. Long-established marine reserves provide researchers with a baseline healthy ecosystem that cannot be fully duplicated with any other methods or models. Even areas closed due to severe environmental damage can provide important data, such as the natural recovery rates of various species and habitats. In particular, such data allows allow a quantitative judgment on the effectiveness of Marine Reserves in facilitating the recovery of fisheries and ecosystems (Hermens, Collie, & Valentine 2003). This type of science that only Marine Reserves can provide is useful not only for examining and adjusting the MPAs themselves, but also for informing and improving management systems outside of the reserves.
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Although there is only limited evidence of the long-term benefits of spillover, such evidence has been increasing, especially as longer-term data has become available (R.A. Abesamis et. al., 2006). Abesamis, et. al. (2006) proposes that a shallow "decreasing gradient of abundance of targeted fish across a no-take reserve boundary" is evidence for spillover. For instance, if a population increases inside a reserve, some of the fish would tend to move away from the more population-dense areas because of resource competition. However, local environmental characteristics can also influence an abundance gradient, since population is usually higher in areas with more resources and in complex habitats (R.A. Abesamis et. al. 2006). One study on abundance gradients of fish across the boundaries of protected areas near two small Philippine Islands (which used a control section without a reserve) found that three of four reserve boundaries had shallow gradients of decreasing abundance. Although habitat factors could not explain the cases where there was sharp decline in abundance across the boundary, the evidence, in general suggests the existence of spillover in many cases (R. A. Abesamis et. al. 2006).
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