The Lummi Nation’s Skookum Creek Hatchery is working with the University of Idaho’s Department of Fish and Wildlife Resources to study a bacterial disease that attacks coho salmon.
Flavobacterium psychrophilus causes the disease, called bacterial coldwater disease, which is often fatal to salmon raised in hatcheries. The bacterial disease is thought to be passed to the next generation within eggs from infected female fish. The disease also can be spread between fish through the water and by fish-to-fish contact.
“Bacterial coldwater disease is a chronic problem at many salmon hatcheries,” said Skookum Creek hatchery manager Bill Finkbonner. “We treat our fry twice with antibiotics to prevent them from becoming infected. If we can find a way to control the disease or cure it, that would be a huge help to hatcheries.”
Without antibacterial treatment, the disease can move quickly through the juvenile population, killing fish with no visible symptoms. When the disease progresses more slowly, it can eat away at the fish’s skin, fins and muscle, eventually exposing the backbone.
“This disease is generally perceived to be the most troublesome bacterial disease of salmon in the Pacific Northwest,” said Craig Olson, the NWIFC fish pathologist serving the Lummi hatchery program.
Finkbonner and Skookum Creek hatchery staff worked with NWIFC pathologists to sample 30 spawning female coho and incubate their eggs. From these 30 females, University of Idaho graduate student Amy Long selected five with varying severities of the disease. Eyed eggs from those females were sent to the university in December where Long will study how the infection progresses.
“There’s strong suspicion that the disease is passed down through the eggs,” Olson said. “This research could prove it and tell us more about how it happens.”