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Warm water killing fish in Mat-Su and Anchorage

  • Author:
  • Updated: May 31, 2016
  • Published August 13, 2015

Unusually warm water temperatures and low river levels are killing salmon in the Matanuska and Susitna valleys. Hundreds of Arctic char, recently stocked by the Alaska Department of Fish and Game, have also gone belly up in Campbell Point Lake, also known as Little Campbell Lake, inside Anchorage's Kincaid Park.

Habitat biologists are calling the conditions "almost a perfect storm," but don't believe the die-offs will have lasting effects on fish numbers in Southcentral Alaska.

"It will have some impact but in the long term for species that return multiple age classes, I wouldn't characterize it as a disaster," said Mike Bethe, Mat-Su area manager for the Habitat Division of the Alaska Department of Fish and Game.

Fish and Game biologists have reported water temperatures as high as 74 degrees in Jim Creek -- a small tributary of the Knik River. Some dead salmon have been found near the river's weir, where Fish and Game staff count incoming fish to monitor and manage the run. Dead fish have been turning up in other Mat-Su streams, including Lucille Creek, Fish Creek and Cottonwood Creek.

This summer has been among the warmest on record for much of Southcentral Alaska, and a lack of winter snow and summer rain have contributed to low water levels.

However, salmon don't all return to freshwater at the same age, even among the same species. Some come back a year early, others a year late. Different age classes of fish returning to a river system each year helps mute the effects of single-year weather conditions that can kill fish -- even if most of them die.

And even with record water temperatures in some Mat-Su streams, many of the fish are still surviving. Bethe said biologists are still recording large numbers of viable salmon swimming up area streams. The returns have been so good for silver salmon that the department has increased the bag limits on the Little Susitna River and many area streams are near or at their escapement goals for the year.

Fish and Game biologists say the water temperatures are coming down from their highs earlier this month.

"Hopefully this weather pattern has changed," said Sam Ivey, Mat-Su area biologist for Fish and Game. "They are reporting that salmon are happier, and looking better."

Fish and Game said that a closure of Jim Creek to all fishing on Mondays an Tuesdays should help the salmon migrate upstream more successfully.

In Anchorage, Fish and Game said that over the weekend of Aug. 8-9 about 500 recently-stocked Arctic char died after water temperatures crested 70 degrees at Little Campbell Lake.

Arctic char are not native to Southcentral Alaska. The fish -- which spawn in lakes in the state's northern areas -- don't do well in warm waters. The state doesn't usually stock Arctic char in Anchorage lakes because, as Fish and Game has learned, the waters are too shallow to remain cold enough for the fish to thrive.

"There was another Arctic Char die-off due to warm water conditions in 2003 at DeLong Lake," said Kristine Dunker, a research biologist with Fish and Game.

But Little Campbell Lake, which covers 8.6 acres inside Kincaid Park in West Anchorage, has a large area that gets up to 18 feet deep. For years, it has been one of the best urban lakes for char fishing, regularly putting out 3-pound fish.

This year, though, surface temperatures into the 70s sucked much of the oxygen from the lake's cooler depths.

"They (the Arctic char) had nowhere to go," Dunker said. "It was either too hot or there was not enough oxygen for them to survive."

Dunker said rainbow trout are doing better in the lake because they can handle warmer water.

And, despite dozens of dead char floating in the lake, several fishermen were still trying their luck on Wednesday.

"I think everything is cyclical," said Josh Witham, 35. "I don't think we need to get freaked out about every little thing."

Witham's fishing partner for the day, 53-year-old Glenn Brown, was more concerned.

"I wonder if the Lower 48 weather is coming our way?" Brown asked. "I hate to see fish dying like this."

Fish and Game officials are less concerned about the warm water fish kills in the Mat-Su and in Anchorage.

"It's just a natural occurrence," Bethe said. "It has happened in the past and it will happen again in the future."

Correction: The story originally said that the Alaska Department of Fish and Game closed Jim Creek to fishing on Mondays and Tuesdays due to warm and low water conditions. According to Fish and Game, the closure on Jim Creek is part of an annual closure on the waterway and not related to fish deaths.

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