Navy divers lend a hand to block screens at Ballard Locks

When someone asks you to close the screen door, you probably don't need to put on a wetsuit and dive 50 feet to do it.

Navy divers spent several hours doing that Tuesday at the Ballard Locks because the salmon couldn't do it for themselves.

They were closing large underwater doors on the Adult Salmon Exclusion Structure, a clinical-sounding name for a 50-by-60-foot mesh screen in the Hiram M. Chittenden Locks. Closing the screen's 10-foot-by-6-foot doors before salmon-migration season begins in mid-June keeps the salmon from getting into the Locks' saltwater drain system where they can get stuck and killed.

The operation required the Locks to be closed most of the day to all but emergency vessels, but few were inconvenienced waiting as notice had been sent to marinas beforehand.

Teams of two divers at a time went under for an hour each for the annual door-closing and cleaning of algae and barnacles off the screen.

Before the screen's installation last year, Army Corps of Engineers spokeswoman Andrea Takash said, hundreds of salmon caught in the drain had to be fished out and moved by hand.

She said the doors will be opened again in mid-September.

Mark Rahner: 206-464-8259 or mrahner@seattletimes.com