Where the Stillaguamish River melds with Port Susan Bay, monitoring continues to show that estuary restoration is working, providing refuge and food sources for juvenile salmon migrating from area rivers to the Pacific Ocean.
“These efforts are making a difference,” said Jason Griffith, environmental program manager for the Stillaguamish Tribe of Indians.
Through two major project phases, the tribe has restored about 320 acres of delta at the zis a ba project site, which adjoins with another about 150 acres restored by The Nature Conservancy.
The recently completed phase 2 of the project incorporated a network of distributaries and smaller tidal channels. These pathways enable freshwater from the Stillaguamish River to disperse more broadly across Port Susan Bay, making portions of the bay cooler and less saline. The channels also give fish navigating through the estuary more pathways to follow.
The tribe is gathering insights about the function of the renewed habitat while planning another major phase of restoration.
Each phase involves setting back dikes or levees to invite water onto a landscape previously converted for agriculture. Reopening the delta to the tides restores critical habitat for the depressed run of Stillaguamish River chinook and other salmon populations.
“This restoration work is designed to provide future generations with access to healthier and more abundant salmon populations,” said Kadi Bizyayeva, vice chair of the Stillaguamish tribal council and fisheries director for the tribe.
Success so far has been evident, with salmon found in freshly inundated marsh and newly carved channels soon after work was complete. Chinook, coho, pink and chum salmon have since been recorded during monitoring, along with trout, common nearshore fish species, and invertebrates important in the marine food chain.
Monitoring occurs biweekly February through July. The goals include better understanding what the capacity is for fish where habitat is restored and learning which populations of salmon are benefiting from the new acreage.
Despite pouring rain one day in May, a team of fish biologists and research scientists navigated a boat into the evolving estuary to conduct this monitoring.
The Skagit River System Cooperative (SRSC), a natural resources management agency that supports the Swinomish and Sauk-Suiattle tribes, leads the monitoring in coordination with the Stillaguamish Tribe.
“We can make predictions about how many fish this could benefit, but we have to get our feet wet to be sure,” said Correigh Greene, senior research scientist at SRSC.
The team moves from channel to channel, hopping onto muddy shorelines, casting a seine and gathering data at each of 14 monitoring sites. Along the way, they note the species and size of each salmon they find. They also scan them for hatchery tags.
If no tag is detected, the team collects a fin clipping for genetic analysis to help determine population origins. When a hatchery tag is detected, the team sometimes keeps the head of the fish to retrieve the tag and determine which hatchery program the fish came from.
Salmon have been intercepted from the Skagit, Snohomish and Stillaguamish river systems, showing the regional value of estuary habitat—an important nursery where juvenile salmon can grow and improve their odds of survival before they swim out to sea—to overall Puget Sound salmon populations.
Above: The monitoring team pulls a seine on shore at one of 14 monitoring locations around the zis a ba project site. Photos and story by Kimberly Cauvel
Stillaguamish estuary restoration gives juvenile salmon more places to rear
