Close up view of a section of barnacle accumulation 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. Barnacles are crustaceans that secrete a fast-curing cement that enables them to latch on to rocks, boats, whales and walls. Scraping barnacle buildup is necessary to help improve salmon’s odds of survival, by reducing their potential for injury or death while passing through the Locks.