FAIRBANKS — When the ice finally disappeared on Quartz Lake on Sunday, a scary and depressing sight appeared — rotting, chalk-white fish carcasses littering the shore and shallows.
It appears the Interior’s most popular sport fishery experienced a massive winter die-off that left hundreds, if not thousands, of dead rainbow trout and arctic char in the 1,500-acre lake about 80 miles southeast of Fairbanks.
“You go around the lake in the shallows, and you see one whitened carcass after another,” said Dean Seibold, who lives on the lake and rents boats to fishermen each summer.
Seibold said he traveled about two miles around the six-mile circumference of the lake and saw hundreds of dead fish. Other boaters reported the same scene along the back side of the lake, he said.
Officials at the Alaska Department of Fish and Game in Fairbanks started getting reports of dead fish frozen in the ice last week from cabin owners around the lake and suspected there had been a winter die-off, said Tom Taube, sport fish research supervisor. In addition, ice fishermen had been reporting low catch rates for the past month or two, he said.
The magnitude of the die-off, however, didn’t become apparent until the ice went out last weekend, he said.
Biologists don’t know how many fish died or how many are left in the lake, Taube said. As of Tuesday, no biologist has been to the lake to survey the situation.
“It’s pretty broad to say it’s total mortality,” Taube said. “It was a fairly large number of fish that died because based on reports by fishermen nobody has caught much in the winter ice fishery in the past couple of months.”
Earl Malcom, 72, is one of those fishermen. Malcom has been fishing Quartz Lake for 40 years. Seeing dead fish scattered along the shoreline that he usually fishes each spring was tough to take, he said.
“I looked at ’em laying there and cried,” Malcom said. “It’s a sad, sad thing.”
While no tests have been done to see exactly what killed the fish, Taube said it’s almost certain it was lack of oxygen, which he attributed to the long winter that kept thick ice on the lake longer than normal. He called it “the perfect storm of conditions.”
The longer the ice stays on the lake, the more the light penetrates the ice, resulting in the growth of plankton under the ice during the daylight hours, he said. That produces an oxygen deficit at night. In addition, the light triggers the decomposition of last year’s vegetation, which also requires oxygen.
“It’s just competing with the fish for oxygen,” Taube said.
Once the ice is gone, the water begins moving and replenishes the oxygen level in the lake, he said.
Quartz Lake has had similar winterkills in the past but nothing as large scale as what was seen this week, Taube said.
“Based on the past history of Quartz Lake, we’re pretty certain this is winterkill,” Taube said. “If it had been a parasite or bacteria, it wouldn’t have done it just in the wintertime; we would have seen it in the summertime.
“If there was something unique to this case, we’d be pursuing looking for something else,” he said.
Judging from a picture he saw, the dead fish “look like they’ve been dead for a while,” he said. As a result, it’s impossible to determine what killed them because the fish are loaded with bacteria and other organisms.
Plans to restock
The department plans to restock the lake three times this summer with approximately 20,000 catchable-size rainbow trout and arctic char. The first load of 6,000 fish was dumped into the lake Tuesday.
“It’s not a good situation, but it’s nothing that means we have to stop stocking it now unless it’s a recurring event,” Taube said. “We’ll keep an eye on it next year. If it happens repetitively for a couple of years, we might have to refigure how we deal with Quartz Lake.”
Some old-timers like Malcom questioned why Fish and Game doesn’t use aerators to pump oxygen into the lake to prevent die-offs like they do in other states such as Minnesota. Taube said using aerators weakens ice because it creates circulation, which creates a safety concern with people driving on the ice. It’s also expensive because it requires electricity.
“Aerators have been talked about in other parts of the state, but it’s not an area we want to go,” Taube said.
The sight of dead fish littering the shores of the lake, some of which were 24 inches or bigger, is one that Seibold has a hard time justifying, though.
“It’s just a crime that all those big fish are gone,” he said.
While Fish and Game began restocking the lake with catchable-size fish in the 9- to 12-inch range on Tuesday, anglers won’t be pulling any lunkers out of the lake for a couple of years, Taube said.
“There will be fish in the lake, but it just won’t be a trophy fishery that it was,” he said. “People can expect catch rates to be down this year. Definitely the density of fish is down with this kind of winterkill.”
Given time, however, fishing should return to normal, Taube said.
“Quartz Lake is pretty productive,” he said. “As long as it doesn’t winterkill for few years, we’ll be back to where we were.”
As of Tuesday, Taube said he hasn’t heard of winterkills in any other lakes around the area.
Contact staff writer Tim Mowry at 459-7587. Follow him on Twitter: @FDNMoutdoors.