Alaska News

Fuzzy fish math: Kenai River may hit its king salmon goal, but doubters remain

A quick math quiz: When does 17,800 equal 15,000? Before your eyes glaze over like a middle-schooler stuck in geometry class on a sunny day, the answer: When you're talking about late-run king salmon numbers on Alaska's most popular sportfishing river, the Kenai.

Hang on for an explanation. But first, the semi-good news.

The Kenai River -- a ribbon of turquoise water 180 miles southwest of Anchorage, was once home to a yearly infusion of Alaska's biggest salmon. In good years, as many as 60,000 kings returned to its waters in July and August.

The last daily count available this year was posted on Aug. 6, when the state's new sonar station -- located 9 miles upriver from the mouth of the Kenai -- counted 251 kings, for a yearly late-run total of 15,131. The minimum escapement goal is 15,000 fish, so it appears enough fish have made it upriver to ensure the run's survival. But it's an illusion. Biologists actually want to see some 16,600 spawners upstream.

"We could, potentially, possibly, make it," said Bob Clark, one of the state's top fisheries scientists. That was about as much certainty as any Alaska fisheries scientist willingly utters about the Kenai River king salmon run. Fisheries science, it turns out, is anything but an exact endeavor.

What is certain is that over the past five years, the number of kings heading up the Kenai has dropped off sharply compared to prior decades. A seemingly constant and constantly changing array of emergency fishing restrictions and closures -- designed to ensure the run's survival -- have clamped down on what was a major source of food, fun, and money for the people who live near the river -- and beyond.

A little more on those numbers

Until this year, the number of kings Alaska Department of Fish and Game biologists thought were needed on the spawning grounds (during the so-called late run from July to mid-August) was 17,800. That number was based on several factors, including a sonar station that pinged sound waves off fish bladders to determine which blips were the large king salmon and which were smaller reds, silvers, pinks and other fish. A problem, according to Fish and Game, is that that split-beam sonar was innacurate. If a smaller fish was sideways in the river, the sonar could mistake it for a king.

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"There was a big margin of error in the counts," said Clark.

This year, Fish and Game installed a different sonar manufactured by Sound Metrics. The company's Didson sonar works more like the sonograms pregnant women get at the hospital. It shows the entire fish, not just the size of its air bladder. Fish and Game believes it to be far more accurate. Sound Metrics even uses images from the Kenai sonar station in its promotional materials. As a result, Fish and Game changed the minimum escapement goal from 17,800 to 15,000 kings for the late Kenai run. Clark emphasized the change is not a lowering of the goal but a change in how the numbers are gathered. Hence, 17,800 equals 15,000.

"It is very complex and difficult to explain, and even I have not yet come up with an easy way for people to understand it," said Clark. "In past years, we were more conservative in estimating the minimum number of fish because of the old sonar," Clark said.

Bad math?

The Kenai River Sportfishing Association doesn't buy the state's math.

"In doing the run reconstruction last winter, the state threw out 14 years of split-beam data, and is now overcounting the number of fish in the river," said Ricky Gease, the group's leader. The KRSA believes the new escapement goal is a lowering of the number. More worrisome, Gease said that so far this year, only 9,200 Kings larger than 30 inches long have been counted.

Kings smaller than that are called "jacks" -- fish that have returned to the river too soon -- and don't have the same success in reproducing as their big brothers and sisters. KRSA is among a number of user groups that believes the state is mismanaging the fishery.

Now as for why 15,000 kings is short of the actual minimum number of spawning fish needed in the Kenai's late run: 15,000 does not account for the number of fish taken by anglers upstream, past the sonar.

Based on surveys of anglers returning from the river, Fish and Game estimates there were 1,600 dead kings upstream of the sonar. So the real number of kings needed at the sonar site this year is more like 16,600.

No one can say for certain why king salmon are not returning to the Kenai, or other Alaska rivers such as the Yukon and Kuskokwim that are facing dismal returns, too. A task force created by Gov. Sean Parnell last year to address the problem has yet to issue a report.

A separate task force was created by Fish and Game too, in part to get the governor's task force the information it needs to finish its work and to modify the Kenai king escapement requirements in light of the new sonar.

Contact Sean Doogan at sean(at)alaskadispatch.com

Sean Doogan

Sean Doogan is a former reporter for Alaska Dispatch and Alaska Dispatch News.

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