Karen Williams takes notes while Christine Terry, in CSI cap, measures a dead coho salmon they found in Miller Creek while conducting their survey.
CSI; Highline volunteers investigate creeks
The CSI team on TV sees a lot of death.
So did the 29 intrepid members of CSI: Highline.
In the case of the fictional Crime Scene Investigation detectives, it is human bodies.
For the Community Salmon Investigation: Highline volunteers, it was dead fish carcasses.
In teams of two, the CSI: Highline volunteers hiked one-mile stretches of Miller and Walker creeks in Normandy Park looking for coho and chum salmon between mid-October and mid-December. Each team had an assigned day to count fish.
When they spotted a carcass, they took measurements and cut open the belly to see the gender and if it had spawned before dying. They then cut off the tail so the carcass would not be counted again during the annual fish census.
What they found was disturbing--an 88 percent pre-spawn mortality rate. The rate was 95 percent for Miller Creek and 57 percent for Walker Creek. Previous studies have shown a 100 percent pre-spawn mortality rate in Des Moines Creek.
“We weren’t surprised by the higher rate in Miller Creek since it is near more roads,” reported Elissa Ostergaard, who provided findings on the CSI: Highline survey at public meetings in Burien and Normandy Park last week.
Ostergaard is the Miller/Walker Creek basin steward under a program funded by the cities of Burien, Normandy Park and SeaTac as well as King County and the Port of Seattle, operators of Sea-Tac Airport.
She concluded that the creeks “are not that healthy.”
Salmon are returning but most are dying before they have a chance to spawn, she noted.
Ostergaard noted the Port of Seattle is doing a pretty good job with its environmental mitigation efforts at the airport but water flow is still too high and there are too many hard surfaces that don’t drain well. There is not enough data to determine if the creeks are getting healthier.
“This is a big problem for coho salmon,” Ostergaard declared. ‘We won’t have many left in our urban areas unless we figure this out.”
She admitted it is easy to get depressed but she pointed to upcoming new regulations and the work of volunteers and basin partners.
She noted the Ambaum storm water detention pond near South 160th Street and 1st Avenue South has been expanded and work is underway on restoring the creeks.
The good news is that scientists are continuing to do research on solutions, according to Ostergaard. Filtering pollution out of the water can be done but it is expensive, she said.
There are several things individuals can do to cut down on the pollution that gets into streams, according to Ostergaard.
These include fixing oil leaks in vehicles, washing vehicles at a commercial car wash, cleaning up after pets, building a rain garden, and volunteering to mark storm drains.
CSI: Highline volunteers counted 216 coho salmon and 56 chum salmon and 45 unidentified in Miller Creek. In Walker Creek, they also counted 216 coho, 57 chum and 24 they were unable to identify.
For coho, that was about the same number as counted last year while the chum count was down. Ostergaard said the chum population in Puget Sound was reportedly high so she speculated many had been caught before entering the creeks.
Since salmon hang around in the creeks for several days they could be counted several times. So experts make an “escapement estimate” of the number of returning spawning salmon. Ostergaard reported the official estimated population was 335 coho and 64 chums for both creeks.
Ostergaard noted volunteers are wanted for the 2013 CSI: Highline count beginning in October. Volunteers are also needed to pull English ivy parks and participate in other restoration projects.
For more information or to volunteer, contact her at firstname.lastname@example.org or 206-296-1909.