TRAIL, Ore. (AP) — Dave Pease always gets a bit nervous when he sends a few hundred thousand of his charges to freedom in a not-so-ceremonious way.
Two Cole Rivers Hatchery technicians force the spring chinook salmon smolts out of the concrete pen that has been their nursery for the past six months. They are swept down a dark, grate-covered canal and then spit out of a pipe and into the Rogue River for a harrowing 157-mile venture to the sea.
“Always a little nervous when we’re kicking them out of the nest,” says Pease, the hatchery’s manager. “You spend all this time raising them, you don’t want anything to go wrong.”
But something has gone wrong with Cole Rivers’ spring chinook. They are not returning as adults in large enough numbers to satisfy sport anglers forced to angle largely for wild spring chinook that they must release during most of the Rogue’s famed spring chinook run.
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But the fish Pease and his technicians sent down the Rogue Tuesday are more than just one batch of the 1.7 million spring chinook smolts kicked loose annually from Cole Rivers.
They are part of a series of short- and long-term experiments meant to hone a new smolt-release strategy that will be designed to get more hatchery spring chinook to survive their two or three years in the ocean and return to fill coolers, barbecues and smokers the way past generations of hatchery fish have.
On the table are such things as truck-rides to salt water as well as tracking myriad variables such as ocean temperatures, fall coast winds and even September rainstorms to gauge whether any of these factors play a role in smolt survival once they join wild chinook smolts in the ocean.
“People are upset that we aren’t getting enough hatchery fish back, and we get that,” says Pete Samarin, an Oregon Department of Fish and Wildlife biologist heading up the experiments.
“The goal here is to maximize the survival of hatchery fish as much as we can,” Samarin says. “We can’t help them survive in the ocean, but if we can time their entry right, we feel we’ll be giving them the best chance for survival.”
In the wild, spring chinook spawn in the fall and their progeny hatch in late winter, fending for themselves until mid to late summer when they work their way downstream and enter the ocean at around five inches long.
Hatchery chinook are spawned in buckets, hatched in…