"Whether we looked at tide pools or studies over the entire world's ocean, we saw the same picture emerging. In losing species we lose the productivity and stability of entire ecosystems," said the lead author Boris Worm of Dalhousie University in Halifax, Nova Scotia. "I was shocked and disturbed by how consistent these trends are; beyond anything we suspected."
The study focused on oceans, but lakes, rivers and other freshwaters were also analyzed over the four-year study. The team looked at 32 controlled experiments, 48 studies of marine protected areas, and global catch data from the U.N. Food and Agriculture Organization's 1950 to 2003 worldwide fish and invertebrates database. They also studied archives, fishery records, sediment cores and archaeological data for 12 coastal regions, making up a 1,000-year time series.
"At this point, 29 percent of fish and seafood species have collapsed. That is, their catch has declined by 90 percent. It is a very clear trend, and it is accelerating," Worm said. "It looks grim and the projection of the trend into the future looks even grimmer, but it's not too late to turn this around. It can be done, but it must be done soon. We need a shift from single species management to ecosystem management. It just requires a big chunk of political will to do it."
The solutions proposed by the researchers included better overfishing and pollution controls and new marine reserves. Forty-eight areas worldwide have already been protected to improve marine biodiversity, and the researchers found that the diversity of species in those areas recovered dramatically along with the ecosystem's productivity and stability.
The National Fisheries Institute, a seafood industry trade association, reported that the trend was not any cause for alarm.
"Fish stocks naturally fluctuate in population," said a statement from the institute. "By developing new technologies that capture target species more efficiently and result in less impact on other species or the environment, we are helping to ensure our industry does not adversely affect surrounding ecosystems or damage native species."
Americans consumed about 16.6 pounds of seafood in 2004, according to the National Oceanic and Atmospheric Administration, up from 15.2 pounds per person in 2000. Joshua Reichert, head of the private Pew Charitable Trusts' environment program, said worldwide fishing is worth about $80 billion in revenue and is the livelihood of some 200 million people. He also said that fish is the primary protein source for more than 1 billion people, many of whom are poor.