Marine Protected Areas Tools for Sustaining Ocean Ecosystems (2001) / Chapter Skim
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Conventional Management of Marine Fisheries
Conventional Management of Marine Fisheries
Pages 30-41
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From page 30... ...
In the United States, the overexploitation of bluefin tuna and of mixed-species groundfish stocks convincingly illustrates the consequences of overcapitalization and excess effort. Problems associated with conventional fishery management that threaten the sustainability of marine fisheries have been highlighted in recent reviews (e.g., NRC, 1999a)
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From page 31... ...
To be effective in the face of this uncertainty requires that the assessments be interpreted conservatively so that stock size is not overestimated and subsequently overfished. Conservative, flexible, and adaptive approaches can compensate for the uncertainty of stock assessments, but frequently these features are lacking from conventional management.
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From page 32... ...
Ecosystem approaches, including marine reserves, will have to be added to the conventional management toolbox to conserve biodiversity, maintain biocomplexity, and ensure that ecosystem services are maintained for posterity. The public's interest in ecosystem approaches in part represents the existence values that the public places on preserving the diverse biota and habitats of the sea (see Chapter 4~.
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From page 33... ...
More conservative quotas and exploitation rates are now recommended, due in part to recognition of our limited ability to estimate and implement FMSY or, for that matter, other target fishing mortalities via catch or effort control. As Hilborn and Walters (1992)
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From page 34... ...
Although spatially explicit components usually are missing, some existing fishery models do recognize that variables other than adult stock size affect
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From page 35... ...
However, recovery of habitat and biological communities may require closures on the order of 5 to 10 years (Collie, 1997~. Conventional Management Tools Management based on the fishery paradigm above centers on measures that regulate fishing activities and the level of catch, rather than on measures that directly promote management of habitat or consideration of environmental variables affecting fish productivity.
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From page 36... ...
However, catchability may change for instance, fishers may increase their efficiency when the stock declines and this could result in overexploitation, a common reason for the failure of conventional management. In addition to measures that attempt to regulate exploitation rate directly, other forms of effort control may be implemented to reduce fishing power, protect vulnerable life-history stages, or increase the market value of the fish.
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From page 37... ...
; most are based on analyzing the way abundance changes in response to known catch levels. In addition to estimates of stock abundance or fishing mortality, conventional management depends on knowledge of what exploitation rates are adequate to derive "biological reference points" that designate both threshold and target levels of biomass and fishing rates.
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From page 38... ...
, and summer flounder (Paralichthys dentatus) with the Atlantic States Marine Fisheries Commission, which represents state interests in migratory species that are fished in the coastal zones and estuaries of Atlantic Coast states.
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From page 39... ...
. It is important to note that if fishery reserves become an important and integral part of management plans, state and coastal regional authorities (e.g., the Atlantic States Marine Fisheries Commission and its Gulf of Mexico and Pacific Coast counterparts)
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From page 40... ...
To provide insurance against stock collapse, scientists have proposed establishing fishery reserves when the lack of accuracy in stock assessments and lack of resolve to fish conservatively make it difficult to achieve sustainable fishing levels under conventional management. The specific causes leading to the collapse of a fishery are controversial because it is difficult to discern the relative contributions of fishing pressure and environmental forces.
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From page 41... ...
choose substantially lower catch rates as fishing targets than in the past (Mace, 1994; Restrepo and Powers, 1999~; (2) implement management tools that are less dependent on stock assessments, such as reserves (Roberts, 1997a; Lauck et al., 1998; Walters, 1998; Murray et al., 1999)
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