In a year with many concerns over salmon abundance in Alaska, the sockeye run at Redoubt Lake near Sitka could be recordbreaking
Subsistence managers on July 7 doubled the traditional harvest limit in order to stem the tide of the massive return which, if unchecked, could far exceed the carrying capacity of the lake.
Note: The Forest Service is doing a recapture study of Redoubt sockeye. If you happen to catch a sockeye with a clipped adipose fin – the little fin between the dorsal fin and the tail – please give the Sitka Ranger District a call and let them know at 907-747-6671.
To participate in the federal subsistence fishery at Redoubt Lake, you must obtain a permit at the Sitka Ranger District Office. Learn more by calling 907-747-6671.
Many Sitkans choose to fish under the state subsistence permit, which can be obtained at the local Alaska Department of Fish & Game office, located on the first floor of the City-State Building at 304 Lake Street. 907-747-6688.
There have been reports of other sockeye runs around the state doing well this season, but Redoubt Lake is a different animal: The lake is fertilized every year by the US Forest Service to support the wild run of sockeye. It’s like fertilizing a garden, and feeding the microorganisms that juvenile sockeye eat. That likely makes it an outlier compared to other runs, but no less of a mystery.
“It’s possible that it’s an anomaly because of that enhancement,” said Rob Cross, who manages subsistence on the Tongass. “But, I really don’t have an easy explanation for it.”
Redoubt Lake is about a 15-mile skiff ride south of Sitka. Surrounded by towering mountains, it resembles an ocean fjord, which it may have been at one time. Its surface is only nine feet above sea level. Much of the lake is below sea level, and is actually saltwater, capped by a lens of freshwater. Given its size, Redoubt Lake’s sockeye run was not particularly strong. So, in1984, the Forest Service stepped in.
“And that was because of concerns of low nutrient levels,” Cross said, ” and that those low levels were potentially restricting juvenile sockeye salmon productivity.”
Managers now aim to have 7,000-25,000 sockeye return to the lake, primarily in July. This year, the first dozen reds came through the weir on June 15, and they have not stopped. As of July 9, 30,000 fish had entered the lake, already 5,000 fish more than ideal. At this rate, there’s a possibility that escapement could hit an unprecedented high of 100,000, and that – although it sounds counterintuitive – is not a good thing.
“In this system like many other systems, we see a point of diminishing returns,” said Cross. “So past large run sizes, generally around 50,000 or more fish have often resulted in a reduced return of the offspring of that spawning generation. And that’s due to carrying capacity factors within the system, like available spawning habitat or food availability for offspring.”
Sockeye swim up the falls in summertime, past the subsistence dipnets and the sport flies and the resident brown bears constantly patrolling the weir, and into the 9-mile long lake. Spawning happens later in the fall, however, and that’s where the bottleneck occurs. Most of these sockeye are crowding into the inlet stream at the eastern end of the lake, digging out “redds,” or small depressions in the gravel where females deposit eggs.
“So we get something called redd super imposition, where essentially fish are kind of fighting for spawning gravel,” Cross explained.
That, plus reduced food availability for the juvenile fish after they hatch, Cross says, are why excessively large parent runs produce small runs of offspring.
There are two overlapping subsistence fisheries at Redoubt. On July 1, the limit in the state subsistence fishery – by far the more popular – was increased to 25 sockeye per day, with a hundred-fish annual limit. Effective July 7, however, the US Forest Service doubled down, and raised the federal subsistence limit to 50 fish per day, with no annual limit, in the lake’s freshwater drainage, which extends over the falls to the mean high tide line.
On July 9, the Department of Fish & Game opened Redoubt Bay to commercial seining for four days.
All in an effort to catch more fish now at Redoubt Lake, so that more can be caught in the future.
Update 7-14-23: This story was revised from its original version to draw a clearer distinction between the federal and state subsistence fisheries at Redoubt Lake.