Though not targeted by the fishing industry, some ocean species often get caught unintentionally in nets or lines used to catch tuna and other commercially valuable fish, says a study presented to scientists today, Aug. 5, at the annual meeting of the Ecological Society of America.

A University of Wisconsin-Madison group's study points to the potential increased risks for the large, slow-growing, slow-to-reproduce animals at the top of food chain.

"It's the sharks, dolphins and billfishes that are hurt the most," says Jefferson Hinke, a University of Wisconsin-Madison graduate student and study group member.

Now, populations of most target species are stable and viable, thanks in part to restrictions on undiscriminating fishing practices such as drift nets and fish aggregation devices. However, any substantial increase in industrial fishing could play havoc with both target and non-target animal populations, Hinke says.

"In these systems, environmental variability tends to have little effect at the top of the food web," he says. "What's really important is the fishing."

Hinke, working under the auspices of the National Center for Ecological Analysis and Synthesis in Santa Barbara, Calif., is part of a group that is developing computer models able to accurately forecast the effects of fishing on major ocean ecosystems. The hope, he says, is to provide fishery managers with a set of tools that can be used to predict change in economically important but ecologically sensitive systems.

The models Hinke and his colleagues are working to develop can help reveal "what happens when you fish off the top of the food chain," says James Kitchell, a UW-Madison professor of zoolog
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Contact: Jefferson Hinke
jthinke@facstaff.wisc.edu
608-262-3088
University of Wisconsin-Madison
5-Aug-2002