Dynamic changes in marine ecosystems: fishing, food webs, and future options

Abstract

Recent scientific literature has raised many concerns about whether fisheries have caused more extensive changes to marine populations and ecosystems than previously realized or predicted. In many cases, stocks have been exploited far beyond management targets, and new analyses indicate that fishing has harmed other species -including marine mammals, seabirds, sea turtles, (deleted: oysters), and sea grasses- either directly through bycatch or habitat damage, or indirectly through changes in food-web interactions. Several scientific papers suggest that fishing has affected food web interactions and altered the structure of marine ecosystems (deleted: in many locations), although these conclusions have been debated. At the request of the National Oceanic and Atmospheric Administration, the National Academies conducted an independent study to weigh the collective evidence for fishery-induced changes to marine ecosystems and the implications of the findings for U.S. fisheries management. The report concludes that ecosystem-level effects of fishing are well supported in the scientific literature, including changes in food-web interactions and productivity of important fisheries, and that food-web interactions should be evaluated in future fisheries management decisions. This will require moving away from traditional single-species management toward a multi-species and ecosystem-based management approach. Society will need to determine which ecosystem components are the most desirable for harvest, and then managers will need to implement policies designed to maximize this desired production while recognizing that other species will be affected. The report recommends a modeling framework be implemented to examine ecosystem interactions and compare the possible outcomes of different fishery management actions. Decisions about management strategies should be made in a manner that accounts for the range of uses involved and their relative social, ecological, and economic values.