Evaluating the Effectiveness of Fish Stock Rebuilding Plans in the United States (2014) / Chapter Skim
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5 Ecosystem Considerations
5 Ecosystem Considerations
Pages 85-96
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From page 85... ...
pro could be used to support rebuilding efforts, but they will not vided initial guidance on inclusion of ecosystem principles be comprehensively reviewed in this report. in the management of the nation's fisheries.1 The decision to In the context of fish stock rebuilding, changes in the include this guidance was based on the perceived realization ecosystem can alter rebuilding rates and the target biomass that traditional management measures were insufficient to level to which an overfished species should be rebuilt.
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From page 86... ...
, "If environmental changes points such as BMSY and FMSY. affect the long-term reproductive potential of the stock or Rebuilding plans require projections of stock dynamics, stock complex, one or more components of the status deterwhich are sensitive to assumptions about the future state of mination criteria (SDC)
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From page 87... ...
. These equilibria are the basis for calculating the biological reference points that are used to determine fish population status and the targets for rebuilding overfished stocks.
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From page 88... ...
The nonequilibrium nature of these models challenges the basis of calculating biological reference points, particularly biomass reference points such as unfished stock size (B0)
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From page 89... ...
The alternation of Pacific sardine, Sardinops sagax, and northern anchovy, Engraulis mordax, in the California Current ecosystem is perhaps the most classic example of attempts to understand ecosystem effects on pelagic fish populations. Jacobson and MacCall (1995)
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From page 90... ...
Productivity may increase, as in the target fishing mortality (FACL) being reduced to as close as Atlantic croaker example, or it may decrease as seems to be possible to zero since 2009, resulting in FACT=0.24 FMSY in the case of winter flounder at its southern range.
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From page 91... ...
. Planque FIGURE 5.2 Biomass and fishing mortality rate of two blue king crab stocks in the Bering Sea: St.
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From page 92... ...
Among these, the alteration of demographic structure be restored. Another consequence is that statistical climateis most relevant to stock rebuilding because depleted stocks population relationships may display recurrent appearance/ disappearance sequences, as has also been observed for a are likely to have truncated age structure and reduced genetic number of populations.
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From page 93... ...
restore the wetlands of coastal Louisiana (Boesch and Turner, The ranges and reproductive habitats of many species are 1984) , which would occur over multi-decadal time frames, likely to shift with climate change, and such shifts may be similar to those of the stock rebuilding plans for long-lived amplified by fishing (Hsieh et al., 2008)
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From page 94... ...
A meta-analysis How should ecological interactions be considered of cod-herring interactions indicated negative effects of when formulating rebuilding plans? The total productivity herring on cod recruitment for several stocks in the North of a fish community is ultimately limited by production at Atlantic (Minto and Worm, 2012)
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From page 95... ...
significant overall reduction in CONSIDERATIONS INTO REBUILDING PLANS fishing mortality (F) is the most comprehensive and immedi A general conclusion is that rebuilding plans should ate ecosystem-based approach to rebuilding and sustaining consider the structure and functioning of populations and fisheries and marine ecosystems." Since that report, there ecosystems in a wider sense to maximize the ability of fish has been a significant overall reduction in F as indicated populations to rebuild.
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From page 96... ...
. 5.9: Ecosystem considerations, among other reasons, argue 5.5: In a multispecies context, growth, maturity, and natural for more emphasis on rebuilding plans that maintain reduced mortality are influenced by the abundance of interacting fishing mortality for an extended period (e.g., longer than the species, although these effects are difficult to predict.
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