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9/22/2006  http://www.capitalpress.info/main.asp?Search=1&ArticleID=27563&SectionID=151&SubSectionID=&S=1  
Fisheries biologist Don Chapman explains the potential effects of climate change on salmon and people to a group of journalists recently near the Snake River in Oregon. - PHIL WRIGHT/ East Oregonian Publishing Group
What happens to snowpack trickles down to fisheries

By CATE GABLE
East Oregonian Publishing Group

The temperate coastal rain forest stands of cedar and spruce are helped by salmon returning their nutrients to the land.

According to Steve Theberge, Oregon State University Extension agent and Sea Grant faculty for Clatsop County, the most important fisheries in terms of economic output for the region are salmon, Dungeness crab and the more than 54 varieties of rock fish in local waters.

"Dungeness crab has been our best money-maker, particularly on the southern Oregon coast. For three years in a row, we've had record takes. We don't really know why. Typically, you don't have three record years in a row for any fishery. It's generally cyclical."

Theberge attributes this success, at least partially, to the effective management of the crab fishery. "Dungeness crab is our most successful fishery. The idea of not keeping females, creating a minimum size limit for catch, and putting escape rings on the traps, that has all worked really well."

He also cited the health of the sturgeon below the Bonneville Dam in the free-flowing portion of the Columbia River. "We think this is the most stable population of sturgeon in the world. They basically know how many are there and what sizes they are. At least we have accurate data about the population." (He warned about taking sturgeon from other areas. According to Theberge, "There are problems above the dams with contaminants in sturgeon.")

But Theberge said that we don't have the same understanding of the complex life of the salmon, nor, therefore, as effective a fishery management plan. Salmon need cold clear waters to remain healthy and to find their way back from the deep ocean to their spawning grounds.

Theberge anticipated problems with the salmon runs as global climate change continues to affect our waters.

Kathleen Sayce, ShoreBank Pacific scientist, agreed. "Wet winters are good for salmon. Warm, dry summers are also tolerable. But overall, salmon are cold-water fish; they can tolerate hot summers but only under certain conditions."

Again, those conditions are changing.

One of the problems salmon and other freshwater fish such as trout will face as climate warming continues is the decline in the amount of snowpack in the Pacific Northwest. Riparian zones - fresh running streams and rivers - depend on snowmelt in the summer to keep water levels high and water temperatures low.

Snowpack is like money in the bank in the Pacific Northwest; it is a store of water that can be used slowly over time as needed.

Less snow and less snowmelt mean that we do not have the reserves of cold water in the hot summers when the fish need them most.

National Wildlife Federation climate specialist Patty Glick said scientists project that in the coming decades climate change could bring a substantial decline in snow accumulation in the Pacific Northwest, especially on the west slopes of the Cascades, the Olympics and the coastal range.

"Our region could see an additional 50 percent decline in average snow pack in the next 45 to 75 years, significantly reducing the primary source of water during dry summer months," Glick said.

Since the late 1940s, average snow pack in the Cascades is down 35 percent. "It takes more precipitation just to get the same amount of snow, and that's because of warming," said Washington's state climatologist Phil Mote.

Precipitation, however, is not a good substitute for snowmelt. Rain often falls too heavily, causing soil and bank erosion and bringing mud and silt into the waterways as it runs off the land instead of slowly soaking in as melting snow does. Clearcutting or loss of trees in areas bordering riparian zones simply aggravates this run-off problem.

Peninsula oyster grower Larry Warnberg said run-off is contributing to salmon degradation. "We are seeing a continued loss of habitat for salmon spawning. And hotter temperatures may mean more fires and more mud in the creeks."

Paula Del Giudice, director of the National Wildlife Federation's Northwest Natural Resource Center in Seattle, said this is so. "Salmon in the region are struggling to survive amidst dams, water diversions and development along river shorelines. Global warming will add an enormous amount of pressure onto what's left of the region's prime cold-water fish habitat."

In a 2002 report issued by the National Resources Defense Council, scientists indicated that "cold-water fish such as trout and salmon thrive in streams with temperatures of 50 to 65 degrees. In many areas, the fish are already living at the upper end of their thermal range, meaning even modest warming could render streams uninhabitable."

As with the oysters, salmon and other species seem to be attempting to adapt to these changing conditions. Theberge said that the spring salmon were very late this year and came in larger numbers than predicted. But he reiterates that scientists have lost their ability to make accurate predictions on what can be expected. This makes it extremely difficult to manage a resource.

"As climate conditions change, fisheries will change, but how is the big question. The biggest thing is the need for fishery managers and those who make their living off the fisheries industry to be flexible. When things change, some things will benefit and some things won't. People making a living off the system will need to make adjustments," said Theberge.

Sayce said another aspect of how continued climate change could affect salmon in their ocean-feeding phase. "The food chain could be disrupted. The krill and phytoplankton in the ocean are on a steep downward curve. Herring that feed on the krill feed the salmon. And that chain could collapse."

Washington State University Extension professor Kim Patten's take on what warmer temperatures will mean points in another direction - conflicts over water. "The reduction of snow for just a few feet in elevation has an exponential change in the total volume of snowpack. Less water is the ultimate result. Salmon, agriculture, people - who will come out on the bottom?"

 
 
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