OREGON STATE UNIVERSITY

Fisheries prof works to improve groundfish assessments

12/04/1997

NEWPORT - David Sampson likens the state of knowledge about Pacific groundfish stocks to driving an automobile in reverse with no rearview mirror.

"All you can see is where you've been," said Sampson, an associate professor of fisheries and wildlife stationed at Oregon State University's Hatfield Marine Science Center in Newport.

And while historical knowledge is important, it doesn't tell fisheries managers much about what the future holds for what has become a multimillion dollar segment of the U.S. fishing industry, one which contributed $60 million in personal income last year to the Oregon economy alone.

That knowledge, or lack of knowledge, came home with a vengeance this fall when the Pacific Fisheries Management Council ordered cuts of between 19 percent and 66 percent in 1998 harvest limits for five groundfish species because of pessimistic forecasts of stock trends.

But Sampson, who is intimately familiar with the methods the council uses to establish harvest guidelines, isn't sure how much better the information will ever get.

Fishermen have long complained that stock assessments - the means of estimating how many fish are available for harvest in a given season - fail to accurately describe how many fish are actually in the ocean. Those same complaints arose during a November meeting of the Pacific Fisheries Management Council where industry representatives called for better, more frequent stock assessments in the future.

To a degree, fishermen have a point, Sampson says.

Stock assessment is a relatively young science in the Pacific, he pointed out. The first assessment survey was conducted in 1979, with updates every three years since then. By contrast, some Atlantic fisheries have been surveying groundfish stocks twice a year for nearly 30 years.

The most common source of assessment data, the survey, typically involves using trawl gear to sample randomly selected reaches of ocean, and counting and weighing the fish that are caught. Pot surveys, by contrast, set traps to catch the fish in various locations. And scientists also use hydroacoustic gear to bounce sound waves off schools of whiting and determine the fish population by measuring the echoes that bounce back.

Fishermen want to see better use made of the logbooks they are required by law to keep, recording information about their catch. The problem, says Sampson, is that the logbooks only record what's happening in areas where the fish are caught.

"The fleet is going to fish where there are fish to be caught," Sampson explained. "If they're catching plenty of fish, but the area containing fish shrinks over time, then the fishery could still be in trouble but we wouldn't know it from the books."

When properly analyzed, logbooks can be useful in providing a snapshot of whether the stocks are increasing or decreasing, he said.

While agencies and some lawmakers are calling for more money to support more frequent stock assessments, Sampson isn't sure the resulting information will reveal more than is known today.

"It's a very big ocean, and we have a very imperfect view of what's going on in it," he said. "We're being asked to forecast the future, but even the best stock assessment, alone, doesn't let us do that. We don't know whether there's another El Nino around the corner, or if there are other shifts in ocean conditions that may be affecting the fish. Even if we had annual data and more sampling, we still wouldn't be able to have great confidence in the numbers that result."

Sampson compares managing a fishery to managing a bank account: You need to know the balance, or how many fish there are, and you need to know the rate of return, or how fast the fish are replenishing themselves.

"Right now, it's as if we're living off the interest, but we don't know how big the balance is, nor do we know the interest rate."

Sampson will be asking fishermen how they think the process might be improved when he discusses stock assessment in Newport on Dec. 10 as part of a free, monthly seminar series sponsored by OSU's Extension Sea Grant. The seminars, targeted at the fishing community, start at 1 p.m. at OSU's Hatfield Marine Science Center. Each talk will be videotaped for future distribution through coastal Extension offices.

For more information or to register for the free series contact Lincoln County Extension Sea Grant agent Ginny Goblirsch at 541-265-3463.