November 12, 2002

Environmental Watch: UW study nets key data on overfishing

SEATTLE -- A new study by a University of Washington professor shows that populations of marine fish may lose genetic diversity even if fishing stops while there are still millions of fish left.

It was previously assumed that number was enough to preserve a diverse gene pool.

Rare genetic variation of little importance today might be the key to adaptability in the future, according to Lorenz Hauser, UW assistant professor with the School of Aquatic and Fishery Sciences and lead author of a report recently published as part of the Proceedings of the National Academy of Sciences.

It could be that genetic diversity in a population needs to be considered when determining sustainable harvests for marine fish such as snappers, rockfish and cod that spend their entire lives in the ocean.

For some animals studied by conservation biologists, such as pandas and elephants, as few as 500 individuals appear to be enough to maintain rare variances. For reasons not yet understood, however, it appears that in marine fishes only a small proportion of individuals produce large numbers of offspring that survive. Therefore as a fish population declines, the number of such capable breeders may reach levels that cannot sustain genetic diversity.

What researchers found is that the number of capable breeders is several magnitudes smaller than they expected.

In their work with a population of New Zealand snapper that was fished down to about 3 million, only one in 10,000 fish was a capable breeder. That means the genetic diversity for a population of a few million fish could be depending on just a few hundred fish.

If such low ratios are commonplace in marine species, many other kinds of marine fish stocks may be in danger of losing genetic variability, the paper says.

Fish scales collected and archived at the New Zealand Ministry of Fisheries provided DNA from two isolated populations of New Zealand snappers for the research. The smaller population from Tasman Bay lost variations in six of seven gene markers as its numbers declined to 3 million between the 1950s and 1998. A larger population from Hauraki Gulf, composed of 37 million fish, showed no loss in variation between the 1950s and 1998. However, it had been fished since the late 1800s and by 1950 already had less genetic variation compared to the Tasman Bay population.

From a practical standpoint, fisheries managers are not going to be able to monitor genetic diversity for every stock, Hauser says. Instead, if scientists can learn which fish are the very successful breeders and why, then managers may be better able to predict the number of offspring produced and thus may be able to increase fishing when conditions are favorable for successful fish and decrease fishing when they aren't.

Hauser was at the University of Hull, England, when the work was conducted in collaboration with Greg Adcock (now of the University of Melbourne), Julio Bernal Ramirez and Gary Carvalho, and their colleague Peter Smith of the National Institute of Water and Atmospheric Research, New Zealand. The study was funded by the Leverhulme Trust, England.

The study, "Loss of microsatellite diversity and low effective population size in an overexploited population of New Zealand snapper," is at http://www.pnas.org/cgi/content/abstract/99/18/11742 .

$257,000 facility benefits trout, salmon

GIG HARBOR -- Chinook salmon and bull trout soon will swim in cleaner water thanks to the new Vactor Decant Station at the Purdy Road Shop in Gig Harbor.

A new $257,000 facility allows Pierce County to treat, monitor and return storm water waste streams safely back into the environment. The system meets or exceeds federal, state and local environment standards, county officials say.

The bottoms of catch basins and interiors of pipes tend to have higher-than-normal concentrations of dissolved metals and oils. If left untreated, the waste may interfere with fish recovery efforts under the federal Endangered Species Act.

Sea-Tac wins environmental award

SEATAC -- Sea-Tac is often at odds with most of its neighbors when it comes to environmental issues, but one community group thinks the airport is good enough to be a green winner.

The Southwest King County Chamber of Commerce has presented the Port of Seattle, which operates Sea-Tac, with the chamber’s Environmental Excellence Award.

The airport has instituted a Recycling and Conservation Program that has led to a led to a 265 percent increase in recycling tonnage, a 30 percent reduction in tonnage sent to landfill, a 14 percent drop in electricity consumption and a 25 percent reduction in natural gas use.

The effort added up to a $1.8 million per year savings in energy and landfill costs.

Michael Feldman, Sea-Tac’s deputy managing director of facilities, said the airport is happy to share with businesses how it reduced waste.

State seeks salmon restoration leaders

OLYMPIA -- A state board is seeking three people to help lead the Regional Fisheries Enhancement Group Program at the Department of Fish and Wildlife.

The three volunteer posts are at-large citizen, sport fisher and commercial fisher. They're three of eight seats on the advisory board that meets quarterly to review and approve salmon recovery proposals from 14 regional fisheries groups.

For information, contact Dianna Ludwig at (360) 902-2252. Send letters and resumes to Ludwig's attention at DFW, Regional Fisheries Enhancement Group Program, 600 Capitol Way N., Olympia, WA 98501-1091.

After turkey, don't forget the salmon

SEATTLE -- Citizens can help welcome back salmon to Piper's Creek from 11 a.m. to 2 p.m. Nov. 29 at Carkeek Park, 950 N.W. Carkeek Park Road. It is one of two upcoming salmon events in the park. The second will be Dec. 7-8.

The day after Thanksgiving, there will be free family activities, including salmon steward tours along the creek, arts and crafts, hot drinks and a bonfire. The annual Salmon Circle Celebration is sponsored by Seattle Parks and Recreation, Seattle Public Utilities, the Carkeek Park Advisory Council and the Carkeek Watershed Community Action Project. For more information, call (206) 684-0877.

From noon to 3 p.m. Dec. 7 and 8, there will be free Piper's Creek watershed tours. Tours will start in Greenwood at the headwaters and follow the creek to watch for salmon. Walkers will see cutting-edge streetscapes and rain gardens.

To reserve a spot, telephone Caitlin at (206) 684-0877 or write caitlin.evans@seattle.gov.

The tour is part of the Living Green Series sponsored by Carkeek Park’s Environmental Learning Center in partnership with Seattle Public Utilities and the Phinney Neighborhood Association. Funding comes from the Puget Sound Water Quality Action Team.

Beautiful fall leaves, ugly flooding

SEATTLE -- Residents can help prevent street flooding by collecting fallen leaves in their yards and composting or properly disposing of them. And those who subscribe to yard waste service may set out two extra bags on their regular collection day in November and December.

Make sure yard waste is "clean green," without garbage or other debris. Do not place leaves in plastic bags, which are not biodegradable. Use paper yard waste bags, a 32-gallon trash can clearly marked "yard waste" or "clean green," or bundle and tie with twine.