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New Menhaden Science Info

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For Immediate Release 5/9/01


Ken Hinman, 703-777-0037




New Report Cites Need to Synchronize Management of Predator and Prey Species


Leesburg, VA. The damage caused by overfishing goes far beyond depleting valuable commercial and sport fish, warns the National Coalition for Marine Conservation (NCMC). Removing too many of one species can adversely effect others in the food web. What the group calls "ecosystem overfishing" threatens not just our goal of building sustainable fisheries, but the balance and health of entire marine ecosystems.


In a new report released this week, CONSERVATION IN A FISH-EAT-FISH WORLD, the NCMC calls on state and federal fishery managers to begin moving away from single-species management toward an integrated, multi-species approach that considers interactions among related predators and prey. The purpose of the report, according to NCMC president Ken Hinman, is to provide managers with guidance as to what predator-prey information is needed and how it should be used in the real world of making fishery decisions, particularly in harmonizing otherwise incompatible management goals.


"A more ecosystem-based approach is a natural outflow of our increasing knowledge of the ocean and our expanding circle of concern for all marine species," says Hinman. "It's a natural progression in the evolution of fisheries management. It's time is now."


Indeed, management decisions are already being influenced by perceptions about the nature and extent of ecological relationships. "Management based on misperceptions is dangerous," Hinman warns. "What we need is a process that people can understand and believe in. "


A number of predator-prey relationships are receiving increased attention in management decisions, underscoring the urgent need for a defined process for conserving related species and managing the fisheries that capture them. The resounding success in rebuilding striped bass along the Atlantic coast, for instance, has been followed by worries that the newly resurgent "rockfish" are finding too little to eat because harvests are too high on one of its most important prey species, menhaden. In Chesapeake Bay, the problem is compounded by fears the low availability of menhaden is causing stripers to increase consumption of blue crabs, already in low supply due to over-harvest.


Scientists have also raised concerns about the fisheries that remove so many of the ocean's apex predators - sharks, billfish and the big tunas - weakening an entire tier at the top of the food chain and causing disruptions down to the ecosystem's foundation. A related concern is increased catches of squid, herring and other forage species that make up a critical part of the diet of these and other overfished species and how it might effect efforts to restore their numbers.


The NCMC urges fishery managers to use the authority they now have to make changes in existing fishery management plans (FMP) and account for the effects that fishing has on others species in the food web. The report offers a template for a step-by-step process for synchronizing management of related predator and prey species under each FMP. It also includes recommendations specific to the management of striped bass, menhaden and associated species.


For the long-term, the conservation group recommends a number of changes in federal law to facilitate movement of all national and regional management bodies away from single-species management toward ecosystem-based management, including development of "ecosystem plans' to serve as overarching guidance and a context for future fishery management decisions.


"The National Coalition for Marine Conservation is committed to moving management of the nation's fisheries toward a broader, ecosystem based approach," says Hinman. "We hope this report will provide drive and direction to this important initiative."


The 28-page report was made possible with grants from the Curtis & Edith Munson Foundation, Donald Slavik Family Foundation and Yamaha Contender Miami Billfish Tournament.


To obtain a copy of the report, please see the "Issue Papers & Reports" section of our publications page.




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Lingering Questions About Striped Bass


By all accounts, the population of Atlantic striped bass is recovered. But what must we do to maintain a healthy population, and have we attained the kind of fishery we want?


The stock assessment for the year 2000 showed a population above the level achieved in 1995, the year the fishery was officially declared "recovered," but the lowest level since 1996. While the four-year decline seems to be leveling off, the erratic population trend seems to suggest that we don't quite have a handle on management of this important species.


Fishery managers, for instance, are still trying to determine at what level to set the target stock size, or long-term maximum sustainable yield (MSY). In the meantime, the 1995 "recovered" level is being used as a proxy for MSY. Some members of the Atlantic States Marine Fisheries Commission - the interstate body in charge of managing this coastal fish - believe that recovery efforts have been so successful we've achieved a stock size at carrying capacity and that environmental conditions are unable to support a larger population. The recent population trend might support this theory, i.e., the stock overshot the optimum level in 1996, decreased in subsequent years and is now leveling off.


Even though the historical striped bass population was larger than today's, they say, deteriorated environmental conditions along the coast, including Chesapeake Bay (where they are known as rockfish), will not allow rebuilding to historical levels.


There is unquestionably some level of population size that the environment could simply never support. But it would be complacent and possibly irresponsible to accept that the 1995 proxy level is "as good as we can do." If prevailing environmental conditions are limiting the number of striped bass, shouldn't we at least consider setting our sights higher and taking action to improve those conditions?


The questions about striped bass that are confronting fishery managers argue for taking a more ecosystems-based approach. A favorite in the striper's diet - menhaden - is heavily fished and not around in the numbers it once was. The resurgent population of hungry bass, not finding enough menhaden, is filling its collective belly with other prey, such as young blue crab. The crabs, the most valuable commercial species in the Chesapeake, are already in decline because of overharvesting. But bay watermen want to reduce the number of rockfish and ease restrictions on crabbing. It could be that human-caused declines of some prey species - menhaden, anchovy, shad - are causing a "natural" decline in others. Are there too many striped bass, or too few other species? That's a fundamental question we need to answer before we concede anything.



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