Management in the Gulf of Maine
The overexploitation of marine resources is a major global environmental problem, overlooked by much of the public. While some threatened living marine resources, such as whales, have garnered a great deal of public attention, depletion of once abundant f
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Management in the Gulf of Maine Andrew A. Rosenberg, Karen E. Alexander, and Jamie M. Cournane
A Personal Perspective The overexploitation of marine resources is a major global environmental problem, overlooked by much of the public. While some threatened living marine resources, such as whales, have garnered a great deal of public attention, depletion of once abundant fishery resources is virtually unknown outside of a rather small community of scientists, policymakers, public interest advocates, and those participating in fisheries both commercial and recreational. For most people, fish is available in the market or restaurants, albeit at rather high prices, so overfishing seems not to be all that widespread. Surveys of public opinion find that most people in the United States believe pollution, not fishing, is the greatest threat to marine resources. Of course pollution is a major environmental problem, but usually a secondorder effect. That is, fishing directly increases the mortality rate of fish or other exploited marine species, whereas pollution may reduce growth, reproduction, or survival in more subtle ways than simple removals. Other anthropogenic impacts such as coastal development, habitat loss, and climate change also impact living marine resources, again through secondorder effects on productivity. But the existence of these other impacts does J.B.C. Jackson (eds.), Shifting Baselines: The Past and the Future of Ocean Fisheries, DOI 10.5822/978-1-61091-029-3_10, © Island Press 2011
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not negate the importance of fishing and overexploitation in depleting fish stocks and fundamentally altering marine ecosystems. Human activities are not independent of one another in their effects on changing ecosystems and in loss of natural productivity. Unfortunately, the impacts exacerbate one another. So, depletion due to fishing may occur more quickly because of habitat loss, and habitat loss in turn may be partially due to fishing activities. For many populations of fish and other organisms, as abundance declines from presumably high levels before fishing occurred, populations compensate for the fishing pressure by increased production through growth and reproduction. This is the basis for much of the theory of fishing and for the expectation that some level of exploitation is sustainable for many biological populations. Overfishing occurs when the rate of mortality due to fishing is so high that the population cannot compensate with increased production so that abundance continues to decline. Fishing at these high rates becomes unsustainable. More complex effects occur when fishing changes age structure, habitat, or subpopulation structure. Unfortunately, we have had ample opportunity to observe the effects of overfishing, both simple and complex. It has long been known that fisheries in general have a tendency toward overexploitation due to the overall economic and business pressures of the industry. Some spectacular stock collapse
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