Tribal hatchery managers are working to save salmon from potentially deadly water temperatures and low flows.
On the Olympic Peninsula, the Makah Tribe’s Hoko Hatchery released chinook three weeks early and sockeye a month early.
“In the summer, we’re usually looking at flows of 100 gallons a minute – we’re already at 160 gallons a minute and it’s only June,” said Joe Hinton, Makah hatchery manager. “Even with the lower flows, I have lots of room to spread them out – but as temperatures go up, I can’t do much about that.”
Temperatures higher than 60 degrees are bad for salmon, because pathogens such as Ichthyophthirius multifiliis (ich) and columnaris (gill rot) thrive in warm water. The diseases spread more quickly when the rivers are crowded by low flows, and can lead to increased pre-spawn mortality.
In 2002, an outbreak of ich on the Klamath River in California killed 70,000 salmon, the most in United States history.
“California has been in this boat for a long time,” said Bruce Stewart, NWIFC fish health program manager. “We started seeing some ich last summer in the low flow, warm water conditions then, and we are setting up for a long, hot summer that will have us in the same boat as California. We are likely to see several other parasites that we haven’t seen for many years as well.”
Some rivers, such as the Stillaguamish, are setting low flow records nearly every day.
“We have the potential of seeing lethal temperatures of water in the Stillaguamish this year – of 75 degrees and no drop-off in the night,” said Kip Killebrew, hatchery biologist for the Stillaguamish Tribe.
“Returning adult fish will find pockets of cool water to hold in if river temperatures are not favorable,” Stewart said. “They will hold in these pockets as long as they can. However, if they have to hold for any length of time in temperatures as high as 70-75 degrees, they will have to deal with fish pathogens that like that temperature range. Egg production in a compromised fish probably will be lower.”
In some instances, hatchery managers may bring adult spawners into their facilities early because conditions will be better in a controlled environment.
The Stillaguamish Tribe is considering a rescue operation if temperatures get too high in the lower river.
“We’d want to get as many fish as we can into cool water and see what happens,” Killebrew said. “If things cool down, we can transport them upriver. If water conditions stay elevated, we would potentially spawn them.”
The effort would be contingent upon the approval of the National Oceanic and Atmospheric Administration.
Tribal hatcheries produce salmon for harvest by both Indian and non-Indian fishermen. Some serve as wild salmon nurseries that improve the survival of juvenile fish and increase returns of salmon that spawn naturally.