Randolph E. Schmid, Associated Press
While seafood forms a crucial concern in their study, the researchers were analyzing overall biodiversity of the oceans. The more species in the oceans, the better each can handle exploitation.
"Even bugs and weeds make clear, measurable contributions to ecosystems," said co-author J. Emmett Duffy of the Virginia Institute of Marine Sciences.
The National Fisheries Institute, a trade association for the seafood industry, does not share the researchers alarm.
"Fish stocks naturally fluctuate in population," the institute said in a statement. "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.
Seafood has become a growing part of Americans' diet in recent years. Consumption totaled 16.6 pounds per person in 2004, the most recent data available, according to the National Oceanic and Atmospheric Administration. That compares with 15.2 pounds in 2000.
Joshua Reichert, head of the private Pew Charitable Trusts' environment program, pointed out that worldwide fishing provides $80 billion in revenue and 200 million people depend on it for their livelihoods. For more than 1 billion people, many of whom are poor, fish is their main source of protein, he said.
The research was funded by the National Science Foundation's National Center for Ecological Synthesis and Analysis.