Some minor vandalism at a downtown Sitka fish hatchery over the weekend created major trauma for some juvenile coho salmon.
The Sitka Sound Science Center reports losing 1,000 coho smolt in the incident, just days before they were to be released into the ocean.
Everything looks like business as usual at the Sitka Sound Science Center hatchery.
Aquaculture program manager Angie Bowers and two techs are transferring around 159,000 coho smolt from several large green tanks — called ponds — into saltwater holding pens in Sitka Sound.
They’ll rear there for another three weeks, learn the scent of the hatchery’s outfall stream, and will begin their 18-month journey into the ocean.
This release would have been 160,000 smolt, except someone entered the hatchery grounds late one night and turned off the fresh water valve supplying one of the ponds.
“Which means they were not getting oxygen?” Rob Woolsey asks.
Right. There was no flow,” Bowers said. “No water coming in. So the level was down and fish were belly-up. She turned the water back on, and a lot came back. But we lost about a thousand, out of 15,000.”
Hatchery intern Maria Savolainen discovered the vandalism and reported it to Sitka police.
So 1,000 juvenile salmon — no big deal, right?
Wild coho, or silver salmon, spend more than a year in freshwater after they’ve hatched, before entering the ocean.
For a hatchery, growing coho to this size — about 24 grams in weight — is a big deal.
These fish were hatched here in the spring of 2016.
“They spend that first whole winter up until April in incubation, and they come out as little more than a quarter-gram,” Bowers said.
“They look like they’re 4 or 5 inches long now?” Woolsey asked
“Yep,” Bowers said.
This is not a huge tragedy, Bowers is the first to admit that.
It’s fortunate Savoleinen came in Saturday to feed the smolt, or the tank may have drained entirely, and killed all 15,000 silvers.
Although ocean survival is impossible to predict, Bowers estimates that if only 8 percent of the lost coho had survived to return in 2019, they would have been worth roughly $1,100 to commercial fishermen.
Nothing else at the Science Center was damaged. This vandalism wasn’t a spree. But it was deliberate.
“It’s not an easy thing to do,” she said. “It’s not something that you could just bump and have happen. It would have to be intentional. We have talked about getting security cameras now. I think that’s probably something we’ll do.”
Bowers said it’s taken a while to rebuild the hatchery’s coho program. A blocked intake upstream in the Indian River in 2010 killed off an entire age class of rearing salmon, leaving an every-other-year gap in production.
Techs collected coho eggs from the river itself to restart coho.
“After this year, we should be back on track.” Bowers says.
Editor’s note: Angie Bowers is a long-time programming volunteer at KCAW, who now serves on the station’s board of directors.