January 16, 2003
Mathematician’s theories hold promise for fisheries management
The key to managing fisheries so populations are stable and healthy may lie in the theories of an 18th century Presbyterian minister and amateur mathematician.
Programmed into computers, the Rev. Thomas Bayes’ mathematical formula helps scientists compare various hypotheses in order to predict how a fish population is likely to behave. And it does this in situations where there are large amounts of information for some variables and a dearth for others.
That’s a pretty fair description of what fisheries scientists face today when assessing fish stocks, according to André Punt, a UW research associate professor of aquatic and fishery sciences.
Punt, the first speaker in this year’s Bevan Series on Sustainable Fisheries (he spoke last week), has done pioneering work the last 10 years on stock assessments using Bayesian techniques, according to Julia Parrish. Parrish, associate professor of aquatic and fishery sciences, and Dave Fluharty, research associate professor of marine affairs, arranged the lecture series in which national and international experts will speak each Thursday afternoon this quarter. The lectures are free and open to the public (see schedule at http://courses.washington.edu/susfish/).
“We need what-if tools for fisheries managers,” Parrish said. Then managers can plug in different approaches, see the likely results and decide what most closely achieves what’s wanted. Bayesian techniques allow one to integrate vast and diverse data sets ranging from the life histories of various species to what’s known about their environment to what’s happened when similar species have been fished in other parts of the world. For example, the Atlantic has been fished longer than the Pacific so that prior knowledge could prove useful to managing Pacific fisheries.
Without ways to integrate many diverse types of information and weigh different hypotheses, the ongoing collection of scientific data doesn’t necessarily make managers’ lives easier, Punt said.
Being able to incorporate the wealth of past and present knowledge with Bayesian techniques is just one needed step.
“Marine protected areas and ecosystem models are also two exciting new tools for fisheries management,” Punt said. Marine protected areas set aside areas of ocean within which fishing and other human activities are restricted. Ecosystem models, which include complex predator-prey relationships are already being used in Alaskan fisheries assessments.
“In the 21st century, fisheries managers will use all these tools to help predict the consequences of our actions,” Punt said.
Ideally, managing fish would be in concert with everything from shipping to oil and gas exploration to tourism. Punt refers to this approach as “ocean management,” rather than “fisheries management.”
In Northwest Australia, in an area the size of half a dozen U.S. states, a groundbreaking effort is under way that has thus far brought together representatives from more than a dozen different groups considered “stakeholders” in coastal and ocean resources, including fisheries.
Of course all those stakeholders — well, for that matter, the entire population of that vast expanse of Australia — could fit into Husky stadium and there would still be a lot of room left, Punt said.
Bringing together stakeholders in any region of the United States would be a much more formidable challenge. In addition there are what Punt refers to as “all the bits of government” that oversee resources here, and a quick tendency to involve lawyers.
To Parrish, the situation cries out for help from universities such as the UW that have expertise about oceanography, fisheries, social sciences, economics and more, as well as modelers such as Punt working to provide a framework that integrates information across all these disciplines.
“We don’t have to tell managers what they should do,” she said, “we just need to give them the power to weigh the options and outcomes themselves.”
On Jan. 16, professor Larry Crowder of Duke University talks from 4:30 to 5:30 in the Fishery Sciences Building’s auditorium about one of the most critical problems when fishing — the capture of animals and fish that fishing crews are not trying to harvest, often referred to as “bycatch.” The Bevan series is named in honor of Don Bevan, a longtime faculty member in fisheries and marine affairs, and was launched in part by donations from his widow, Tanya.
