Threats to the ocean : on the role of ecosystem approaches to fisheries

It is becoming increasingly clear that humans impact marine ecosystems and their biodiversity to a very considerate degree, and evidence of the scale of impact is growing. An enabling factor for this has been a change in focus from local-level studies to increased emphasis on meta-analysis of global or regional-level analysis of fisheries' impact. Results include the facts that the world's total fish catches have been decreasing over the last decade or more; that larger, predatory fishes (table fish) are becoming increasingly scarcer; and that we are appropriating the ocean shelves' primary productivity to the same level as we are for terrestrial ecosystems. Ecosystems are being eroded in countries throughout the world, and though one might get the impression from the IUCN Red List that it is mainly a developed-country problem, it is alarming that the impact of severe overfishing may be on an even larger scale for developing countries. We describe aspects of the risks overfishing poses to marine ecosystems, and point out how ecosystem approaches to fisheries can be used to evaluate the potential impact of alternative fishing policy scenarios.