INCREASING FLUCTUATIONS IN flows for Puget Sound rivers, including the Elwha, over the past 60 years provide some bad news for threatened chinook.
More noticeable fluctuations in flow can wash away salmon eggs and tire out the young fry, especially when low flows force adult fish to deposit their eggs in more exposed areas in the center of waterways.
That is the conclusion reached in a new National Oceanic and Atmospheric Administration and state Department of Fish and Wildlife study published in the peer-reviewed journal Global Change Biology.
The study pointed to increased flow variability as having the most negative effect on salmon populations of several climate factors considered.
“There’s more flooding in late fall and winter,” said Eric Ward, an ecologist at NOAA Fisheries’ Northwest Fisheries Science Center in Seattle and lead author of the research.
“This is happening when the eggs are in the gravel or when the juveniles are most susceptible.”
Research found that changes in river flow have increased since 1950 in 16 of 20 salmon rivers examined, with 11 rivers including the Elwha, Skykomish Snoqualmie, Skokomish and Puyallup showing statistically significant increases of about 35 percent.
The increased variation has occurred even with no change in the average overall winter flow.
There was no word on whether the dam removal projects on the Elwha had any impact on the river’s flow data.
The good news, especially for the rehabilitating Elwha River, is that many salmon habitat projects restore and reopen side channels and floodplains that provide rearing habitat for young salmon and refuge from fluctuating flows.
Actions to reduce stormwater runoff in ways that allow water to infiltrate and move more slowly through the ground can also ease flooding and peak flows that otherwise threaten salmon redds.
The researchers weighed several climate factors in freshwater and the ocean to determine which had the greatest effect on salmon numbers.
Freshwater factors included overall winter flows, peak flow timing and winter flow variability.
The ocean factors included upwelling of nutrient-rich water and the Pacific Decadal Oscillation, a large-scale marine temperature pattern.
Of all the factors, the study found variation in winter river flows had the strongest influence on salmon populations, reducing their growth rate.
“Rivers are dynamic environments, and some level of variability is to be expected in natural systems,” said Joseph Anderson, a fisheries biologist at the state Department of Fish and Wildlife and coauthor of the new research.
“The point here is that as strong variability becomes more common, it eventually begins to have a negative influence on populations.”
And that variability becoming more common is one of the thrusts of climate change science.
It’s not so much global warming as the volatility of temperature and weather that can wreak havoc.
“We’re not talking just about warmer temperatures, but a more variable environment with more extremes on either side,” Anderson said.
“As these extremes get farther apart, the result is a negative impact on salmon.”
The study points to climate models predicting increasingly severe storms and droughts and, in the Pacific Northwest, more precipitation falling as rain instead of snow.
That means rivers that rise and fall much more sharply and with more frequency.
This makes life tough for young hatchlings that spend their first few months in freshwater before a migration to the Pacific Ocean.
Advise Fort Worden
The Fort Worden Advisory Committee is seeking qualified applicants to fill a vacant at-large position.
Committee members serve a three-year term.
The advisory committee was established in 1973 by the State Parks and Recreation Commission “to provide assistance and recommendations for the development and operation of Fort Worden State Park.”
The Fort Worden committee is the longest-standing advisory committee for Washington State Parks, and is the model after which committees at other state parks have been formed.
The 17-member panel includes representatives from park leadership, park partners, historic interpretive groups and local government.
There are also six at-large members to represent the community.
The committee meets monthly on the third Thursday at noon at Fort Worden State Park in Port Townsend.
The committee’s charge is to serve in an advisory capacity and as a resource on matters relating to the development and management of the park.
Applicants should submit a letter of interest — outlining specific interests and skills they might bring to the Advisory Committee and the Fort Worden community — to Vice Chair Ron Kubec, Fort Worden Advisory Committee, 200 Battery Way, Port Townsend, WA 98368 or by emailing ronkubec@cablespeed.com.
Letters are accepted until Feb. 16.
Anglers meeting
Kevin Long, project manager of the North Olympic Salmon Coalition, will speak to the East Jefferson Chapter of Puget Sound Anglers at 6:30 p.m. on Tuesday.
The talk is set for the Port of Port Townsend commissioners office at Point Hudson, 333 Benedict St., in Port Townsend.
Refreshments will be served and the public is invited.
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Outdoors columnist Michael Carman appears here Thursdays and Fridays. He can be reached at 360-452-2345, ext. 5152 or at mcarman@peninsuladailynews.com.
