With multispecies management in the Chesapeake scheduled to get underway in 2007, state management agencies will be looking for help from fisheries scientists - and models such as Ecosim-Ecospace-Ecopath - to help assess the implications of alternative policies. For example, if monitoring of striped bass populations suggests that catch limits could safely be raised, managers could use models to assess potential impacts on croaker, weakfish and bluefish with regard to common prey such as menhaden. They could also ask how such an increase is likely to affect menhaden directly or blue crabs. Models are a tool, says Alisdair Beattie of NOAA's Chesapeake Bay Office. "We don't go to them to give us absolute answers," he says, "but we can use them to predict the expected directions and relative magnitudes of fishing policies."

The best models, meaning those that well characterize food web and related processes, are only as good as their data. Despite the fisheries monitoring conducted by both Maryland and Virginia over the last several decades, the kind of data scientists need, especially on predator-prey or food web relationships, has been sorely lacking. To begin obtaining those kinds of data, the NOAA Chesapeake Bay Office is supporting survey efforts at two research laboratories, the University of Maryland Center for Environmental Science (UMCES) and the Virginia Institute of Marine Science (VIMS).

At the UMCES Chesapeake Biological Laboratory, Tom Miller is overseeing the Chesapeake Bay Fishery-Independent Multispecies Survey (CHESFIMS), a collaborative effort with the Maryland Department of Natural Resources that conducts intensive bi-monthly surveys of the mainstem Bay and shoal water areas (depths less than 30 feet that border the mainstem Bay). They've been compiling details on species that are most prevalent by number and weight. In 2002, for instance, in May and July, Bay anchovy was the most frequent species coming up in nets, but they were third and fourth in biomass, respectively, compared with blue crab, which led all species. These data, says Miller, will help researchers determine the food web relationships that are essential for multispecies models.

At VIMS, Chris Bonzek is heading up the Chesapeake Bay Multispecies Monitoring and Assessment Program (CHESMMAP), an extensive survey effort that complements the CHESFIMS program by targeting larger fish in the Bay mainstem. "Monitoring is not glamorous," says Bonzek, "but it is critical if we're going down the path of multispecies management. We need long-term data on patterns of feeding habits," he says, for example, "to better understand changes that could be occurring in the Bay and which our models will have to account for." Visit their web sites to see survey findings from both programs at hjort.cbl.umces.edu/chesfims.html and www.fisheries.vims.edu/chesmmap.

This page was last modified February 06, 2004

h/V02N4/side3