Scraping Barnacles Gives Salmon A Fighting Chance

USACE/SEATTLE DISTRICT
Published Dec. 20, 2023
Corps of Engineers employees volunteer to scrape barnacle buildup along the filling tunnels.

Corps of Engineers employees volunteer to scrape barnacle buildup along the filling tunnels at Lake Washington Ship Canal and Hiram M. Chittenden Locks, Seattle, Dec. 12, 2023. Seattle District is capitalizing on the additional large lock dewatering events from the large lock center miter gate replacement project, to scrape the barnacles before juvenile salmon begin migrating.

A Corps of Engineers employee scrapes barnacle buildup along 14-foot-tall filling tunnels.

A Corps of Engineers employee scrapes barnacle buildup along the 14-foot-tall filling tunnels at Lake Washington Ship Canal and Hiram M. Chittenden Locks, Seattle, Dec. 12, 2023. Barnacle scraping helps improve salmon’s chances of survival by reducing their potential for injury or death while passing through the structure.

A Corps of Engineers employee scrapes barnacle buildup along 14-foot-tall filling tunnels.

A Corps of Engineers employee scrapes barnacle buildup along the 14-foot-tall filling tunnels at Lake Washington Ship Canal and Hiram M. Chittenden Locks, Seattle, Dec. 12, 2023. Barnacle scraping helps improve salmon’s chances of survival by reducing their potential for injury or death while passing through the structure.

A Corps of Engineers employee scrapes barnacle buildup along filling tunnels.

A Corps of Engineers employee scrapes barnacle buildup along the entire length of the 800-foot-long, 8-foot-wide by 14-foot-tall filling tunnels at Lake Washington Ship Canal and Hiram M. Chittenden Locks, Seattle, Dec. 12, 2023. The Corps of Engineers is mandated to scrape the barnacle buildup once a year to make the large lock safer for juvenile salmon going through it as they migrate out to sea.

Photo of people in safety gear scraping barnacle buildup along filling tunnels.

Corps of Engineers employees volunteer to scrape barnacle buildup along the filling tunnels at Lake Washington Ship Canal and Hiram M. Chittenden Locks, Seattle, Dec. 12, 2023. Barnacles pose a threat to salmon journeying through the Locks out to sea. Scraping them off helps improve salmon’s odds of survival by reducing their potential for injury or death while passing through the structure.

Photo of a person in safety gear scraping barnacle buildup along filling tunnels.

A Corps of Engineers employee scrapes barnacle buildup along the entire length of the 800-foot-long, 8-foot-wide by 14-foot-tall filling tunnels at Lake Washington Ship Canal and Hiram M. Chittenden Locks, Seattle, Dec. 12, 2023. The Corps of Engineers is mandated to scrape the barnacle buildup once a year to make the large lock safer for juvenile salmon going through it as they migrate out to sea.`

Barnacles, barnacles everywhere!

Secreting a fast-curing cement, these crustaceans latch themselves on to any hard surface - rocks, boats, whales and walls – and hold on for life. But don’t let these sticky sea creatures fool you.

Barnacles pose a clear and present danger to salmon journeying through Lake Washington Ship Canal and Hiram M. Chittenden Locks (Locks), Seattle, out to sea.

Salmonids, especially Endangered Species Act-listed salmonids, Chinook salmon and steelhead, migrate through the Locks twice in their lifetime as juveniles heading out to sea and adults returning to spawn.

Before, during and after migrating, salmonids battle a host of threats: predators, environmental conditions, disease, oceanic parasites, spawning streams, or just bad luck (like getting crushed as eggs in the gravel or stuck out of water if their streamflow drops) and barnacles, to name a few.

That’s why every year, U.S. Army Corps of Engineers employees scrape the barnacle buildup along the entire length of the 800-foot-long, 8-foot-wide by 14-foot-tall filling tunnels at the Locks. This year’s group of Corps of Engineers employee volunteers came out Dec. 12 to support the cause.

“We scrape the barnacles to make the large lock safer for juvenile salmon going through it as they migrate out to sea,” said Locks Fisheries Biologist Kaitlin “Katie” Whitlock.

Scraping barnacles isn’t just something the Army Corps wants to do; it’s something it MUST do.

“We have an ESA requirement to scrape barnacles once a year,” explained Whitlock. “The Corps can help improve salmon’s odds of survival by reducing their potential for injury or death as they pass through the Locks.”

The Lake Washington co-managers, Muckleshoot Indian Tribe and Washington Department of Fish and Wildlife, count adult salmon between June 12 and Oct. 2 annually. So far, five-year averages of salmon going through the Locks are 11,455 (Chinook), 30,216 (Sockeye), and 17,448 (Coho).

Fewer reach their spawning grounds due to predation, harvest, disease, parasites, environmental conditions and other unknown reasons.

Seattle District is capitalizing on additional large lock dewatering events from a large lock center miter gate replacement project, to scrape the barnacles before juvenile salmon began migrating.  

Although there are quicker ways to scrape barnacles, hand scraping remains the best because there is no mechanical process that removes barnacles more efficiently and no chemical that would not harm fish.

After a mandatory morning safety briefing and donning safety gear of rubber boots, hard hats, coveralls, gloves, ear plugs and face shields, volunteers climb 55 feet down scaffolding to the large lock’s bottom, gaining a rarely seen view of the empty structure.

This stint isn’t for the faint of heart — you shouldn’t be afraid of heights or confined spaces.

Whitlock divides the 25 volunteers into two groups, one for each tunnel, and takes them through the tunnels and connecting conduits along each side of the large lock chamber. After choosing their scrapers, they pick their wall sections and start scraping barnacle accumulation along the two tunnels running the entire chamber length.

The scraping sound is deafening, the fishy smell is pungent.  

But working as a team to help salmon journey out to sea safely and ensure future fish populations in Puget Sound – Priceless.

“It’s a super fun, rewarding experience, working with great teammates every year and meeting new people,” said Ross Emry, meteorological technician with Water Management (Hydrology and Hydraulics). “It’s a lot of work but I love it. I’ll come back for a fifth time,” the 20-year district employee who’s been a volunteer barnacle scraper since 2020, added.

This is Seattle District Equal Employment Opportunity Manager Gracie Lyon’s first year volunteering. It’s also the first year (since she began with the district) she wasn’t scheduled to visit a project site. “I wanted to come out and get to know my fellow employees, outside of my normal EEO role.”

Lyon is already committing to volunteer next year, promising, “The EEO office will be in charge of refreshments.”

Barnacle scraping always occurs after large lock dewatering; by that time there isn’t anything interesting left to find. But in previous years, volunteers found a six-foot white sturgeon, juvenile harbor seal, colorful anemones and starfish, a few squid, multiple cell phones and even a diamond ring.