Doing the least amount of harm through fisheries management means taking a "precautionary approach," an ethic that has been embraced globally and has been gaining momentum in the United States, including the Chesapeake Bay. In essence it means not taking actions in fisheries that will risk the long-term sustainable yield of fisheries productivity we want to exploit. It means, for example, that "you need to consider your activities before you risk destroying habitat," Houde says, "before you risk destroying predator-prey relationships that are important in supporting the productivity of those fish you want to harvest."

Houde's answer is that the best course lies in adopting the ethic of doing the least amount of harm or no harm to the ecosystem in the face of great uncertainty.

Still, the precautionary approach is not without controversy - it reflects a change from traditional management in that it is "risk averse." As Paul Dayton remarks in Science magazine, "resource management faces strong economic barriers to risk-averse strategies. These polices cannot be expected to be implemented until the burden of proof is placed on exploiters of public marine resources to prove that they do not cause damage rather than simply assuming this to be the case until demonstrated otherwise."

The United Nations Food and Agriculture Organization (FAO) has been a strong advocate of the precautionary approach and risk-averse management and has sponsored international meetings of all fishing countries and produced documents with a wide impact. "In management plans in most fishing countries around the world," says Houde, "people have bought into the precautionary approach." Fisheries councils and commissions in the nation's coastal regions are beginning to adopt approaches that reflect this. For example, the Atlantic States Marine Fisheries Commission, which manages Atlantic menhaden stocks on a coastwide basis, adopted an amendment to the Menhaden Fishery Management Plan in 2001 that contains a new overfishing definition for the Atlantic stock that uses a "fishing target and threshold" and "stock size target and threshold" instead of MSY, maximum sustainable yield. Targets and thresholds are measures of how the precautionary approach could be adopted, says Nancy Butowski. Maryland DNR has a commitment to multispecies and ecosystem-based fisheries management, she says, and has recently selected five key species - oysters, blue crabs, striped bass, menhaden and alosids (a collective term for all four Alosa species - American shad, hickory shad, alewife and blueback herring) - to begin with. "We will be spending a lot of time on how to revise and amend the fishery management plans for these species."

What considerations would need to be taken into account if the striped bass fishery was managed from a multispecies and ecosystem-based perspective rather than on a single-species basis? While we would first of all want to protect water quality, Houde says, we would also want to preserve some part of the menhaden biomass for consumption by striped bass. To do that, "we would need to determine what level of biomass is needed to sustain a healthy striped bass population in the Chesapeake. We would need to know about the role of anchovy and blue crabs as alternative prey. We would also need to know the impact of different anchovy and menhaden levels on consumption of crabs by striped bass. For example, if anchovy and menhaden consumption increases, what will it mean for the consumption of crabs? If striped bass catch is to be maximized, what will this mean for other species, both predators and prey? What are the interactions between striped bass and menhaden: can we expect to have more or less phytoplankton if we fish one or the other?

To answer such what-if questions, managers need to employ fisheries models that can offer some assurance about their predictive trends. Such models must be able to integrate food webs and a host of ecological parameters. In the last several years, the NOAA Chesapeake Bay Office has been working with scientists and resource managers on adapting three sets of models, Ecopath, Ecosim and Ecospace. The models begin with snapshots of food web relationships (Ecopath), while Ecosim adds in the behavior or vulnerability of a group of organisms; Ecospace takes the Ecosim model and, in effect, makes it into a movie. This enables managers to pose the what-if questions, says NOAA's Alisdair Beattie. "We don't use the models to predict absolute abundance," says Beattie, "but we try to re-create patterns of abundance that occurred in the past." If the model can hindcast such patterns, then it could potentially be used to try to forecast the impact of different fishing policies, a useful tool for resource managers.

While models come with inherent uncertainties, even when they are "validated," the best are limited by the quality of data they employ. A 1998 report that first explored the potential of multispecies management in the Chesapeake concluded that the monitoring of economically and ecologically important species then underway was inadequate for estimating abundance and providing critical biological data. Today, two major monitoring projects are underway in Maryland and Virginia, CHESFIMS and CHESMMAP, respectively (see sidebar, The Need for Monitoring). These Baywide surveys measure abundance, diversity and recruitment success of key species and will be important for emerging multispecies management.

The Chesapeake Bay Program is committed to begin multispecies management by 2007. The kinds of changes watermen like Bootie Collins will face are as yet uncertain. These changes could eventually be reflected in different allocations for striped bass or regulations related to handling bycatch. "There could be times and places," says Houde, "where certain kinds of gears and certain kinds of fishing should not take place, for instance, if you don't want to catch too many young fish of a target species or a fish that supports target species or a threatened species." There might be kinds of fishing that can be avoided or minimized in some areas. In the long run, it could make a difference for pound netting and gill netting, he adds. For now, Collins and his crew can expect to keep discarding stripers that don't measure up, or to change to more selective gear that will accomplish the same ends more efficiently.

The movement towards ecosystem-based fisheries management does not reflect a revolutionary change; rather it reflects an evolution that has intensified since the early-1970s, when the first scientific papers on multispecies issues appeared. Calls for new ways to manage our fisheries have intensified worldwide as scores of popular species have become unsustainable for commercial harvest and important habitats have been destroyed by pollution and by fishing practices themselves. The Chesapeake is no stranger to this phenomenon: oyster reefs hardly exist anymore and underwater grass habitats are a fraction of what they were; meanwhile, species like sturgeon and shad that once thrived are so depleted that fishing for them remains forbidden.

Bay Program commitments to reversing declines in water quality and to rebuilding habitats provide a basis for holistic approaches to managing the Chesapeake's fisheries. The traditional single species approach, primarily for controlling catch, helped solve certain problems in the past, but it often overlooked others. Whether successful ecosystem-based management will mean that we can have both abundant fish and blue crabs, both large menhaden harvests and healthier, fatter striped bass in Bay waters remains to be seen - undoubtedly, there will have to be tradeoffs. The role of fisheries research in this case is to provide the tools that will give managers and stakeholders a measure of confidence in facing the tough choices that lie ahead.

This page was last modified September 15, 2018