Groundwater allows trout at local hatchery to survive warm weather

Fish at the Fraser Valley Trout Hatchery have survived hot spring and summer, but stocking of lakes had to be halted early.

Groundwater allows trout at local hatchery to survive warm weather

Fish at the Fraser Valley Trout Hatchery have escaped the effects of warm weather that killed thousands of trout at a Bellingham facility last month.

Nearly all the trout at a hatchery in Whatcom Falls Park died in two separate events in July, the Bellingham Herald reported last week. Around 5,400 rainbow trout destined for local fishing lakes died, with only “a couple hundred surviving.”

High water temperatures were blamed for the die-off at the hatchery, which uses water from the shallow part of a nearby lake.

Despite similarly high temperatures in Abbotsford, the Fraser Valley Trout Hatchery’s Dean Worrall said trout at the local facility have escaped harm because it relies on groundwater.

“We’re faring OK,” he said, because the water at the hatchery comes from an aquifer and remains at a constant temperature throughout the year.

Hatchery workers had to stop stocking lakes sooner than usual out of concerns that the shock of going from the hatchery’s cold water to a warm lake would kill the trout.

“Usually we do OK with temperatures until the end of June, but this year by the end of May we were running into very high temperatures, especially in some of our local lakes,” Worrall said.

“We were running into water temperatures that were 25 degrees.”

While Worrall said  water temperatures that exceed 22 degrees can kill trout, he said those places where fish were stocked have been “reporting OK.”

That’s not the only problem posed by the high river temperatures.

In early summer, the hatchery usually transfers steelhead and cutthroat trout to other facilities where they can grow larger before being released.

This year, higher temperatures at those river-fed facilities have halted those transfers.