Coho run strong in Agency Creek

By Nicole Montesano

Smoke Signals staff writer

Agency Creek comprises a mere fraction of the massive Willamette Basin. Yet this pretty, tree-lined stream is home to a unique strain of wild coho salmon that makes up 4 to 6% of the total coho runs in the Willamette — an average of 300 fish annually, although Aquatic Biologist and Tribal member Brandon Weems said it has dropped as low as 200 and has gotten as high as 1,200.

“To get that much back is a pretty big deal,” Weems said.

Why the creek hosts such a substantial percent of the run is something of a mystery, but Weems attributes it at least partly to the Tribe’s stewardship. Logging operations on reservation land are required to leave 150-foot buffer along the stream and a 75-foot barrier along any perennial streams, to ensure plenty of shade cover over the water, and the Tribe also operates a water quality program.

Woody debris was added to the stream to create channels and habitat where tiny smolts can hide from high flows during storms and find plenty of insects to eat.

 The Tribe improved 14 crossings over the creek to open 23 miles of additional salmon habitat that had been blocked.

Weems said much of the work consisted of replacing culverts that were perched too high for fish to get into, with either round culverts or open bottom culverts, and in a few instances, putting in bridges.

“They spend a full year in Agency Creek as juveniles, fighting for the same resources, so the more area you’ve got, the better for them,” Weems said.

The Tribe also brings in additional coho carcasses from hatcheries, to spread along the streambanks.

“Bears, birds and anything you can think of come and get them, and it does provide some fertilizer for the riparian area,” Weems said. “You have to remember that historically, the salmon runs were much larger, so they had much more of that.”

The Tribe is careful to bring in only coho carcasses, he said, for fear that species not native to the creek could introduce parasites or viruses to the juvenile fish.

The chances of a juvenile salmon surviving to spawn are not high, Weems said. Out of thousands that leave Agency Creek for the ocean, a mere 300 or so make it back most years. Part of that may be the arduous journey.

“Coho have to travel 250 miles from the ocean to Agency Creek, through the Columbia, the Willamette and the Yamhill,” Weems said. “By the time they get here, they’re pretty tired.”

The journey takes about two months, he said.

Agency Creek also hosts lamprey and a run of winter steelhead, so tiny that just four to eight fish return every year. Rainbow trout — the same species as winter steelhead — live in the stream as well, and it’s unclear why some strike out for the ocean and some choose to remain, Weems said.

In November of last year, with the creek swollen by rains into a rushing torrent, coho leaped up through the rapids again and again, often being swept back over the shelf they had just gotten over. Undeterred, they kept trying, while those that made it rested at the side in a tiny space of quieter water for a while before resuming their journey.

Every year since 2011, the Tribe has held a First Fish ceremony on Agency Creek, leaving the bones in the river to call their kin home for the Tribe, along with their promise to honor the fish, in keeping with the ancient agreement between the Tribe and the salmon people.