H&N's: Heat raises concerns about local fish

Heat raises concerns about local fish

H&N photo by Julia Carr Green algae line the shores of Klamath River south of Lake Ewauna Thursday afternoon. Hot water combined with algae blooms is threatening fish in the lake and river. Dying algae draw oxygen from the water, in turn killing the fish.

August 5, 2005

Klamath Falls Herald and News

By DYLAN DARLING

Conditions are ripe for fish to die in the waters near Klamath Falls, federal officials said Thursday.

Algae blooms are thick in Upper Klamath Lake, Lake Ewauna and the portions of Klamath River the lakes feed. The water is warm, as is the air above it. If the hot conditions start killing the algae, they will in turn start killing fish by sapping their oxygen.

Officials wait and watch the temperatures.

"They are high enough now. We are hoping they don't get up anymore," said Cindy Williams, chief of natural resources for the Klamath Reclamation Project.

After a week of 90-degree heat, 100,000 fish, mostly small chubs and minnows, went belly up around July 21. Also dead were several thousand yearly, or year-old or less, endangered sucker fish.

The fish were found along a seven-mile stretch of the Klamath River below Klamath Falls.

Water temperature near the time of the fish die-off had climbed to 82 degrees. Scientists say suckers can survive in water as warm as 75 degrees, but it starts to take a toll on them.

The Bureau Reclamation is tasked with keeping water levels up in Upper Klamath Lake for the suckers, while also maintaining flows down the river for threatened coho salmon and providing a diversion for the Project.

The only way to prevent a fish die-off is for temperatures to take a turn for the cooler, Williams said. Having more water in the lakes or river would not help if it is more hot water.

So far, the July fish die-off has been an isolated incident.

"We had had cooling conditions since," said Rich Piaskowski, a fisheries biologist for the Project.

But now things have heated up for a couple of days, and highs are expected to be in or close to the 90s through the weekend.

Along with the return of hot weather the past couple of days, there have been low winds and cloud cover - priming things for a possible fish die-off, Piaskowski said.

During the day, algae creates oxygen, but at night and when it dies the algae consumes oxygen. When the algae starts eating up more oxygen than it puts out, it can leave little for fish.

Currently, the water is green with algae.

"It's kind of like pea soup," Williams said.

To see if the soup turns lethal, officials are asking for help. Those who notice dead fish in bodies of water near Klamath Falls should call Roger Smith, a Oregon Department of Fish and Wildlife biologist, at 883-5732.