A brief history of Susitna salmon

A brief history of Susitna salmon management begins when the first escapement goal was set for Susitna sockeye in 1979.

A Bendix sonar counter was placed into service about that time to measure the escapement. In the late 1980s, the goal was revised based on a study of 24 sockeye-producing lakes in the Susitna drainage.

The purpose of an escapement goal is to ensure sustainability and maximize yield (harvest). State policy requires that escapements goals must be scientifically defensible.

For over 25 years there was a perception that the sockeye returning to the Susitna River were not meeting the escapement goals. This was driven by the assumption that the Bendix sonar counter was accurately counting the sockeye escapements. The perception led to numerous time and area restrictions on the Central District drift fleet and Northern District setnets.

The escapement counts in the Susitna were periodically called into question, particularly after the 1989 season when the Exxon Valdez oil spill caused drift gillnetting to be closed in Cook Inlet. The closure resulted in a large over-escapement in the Kenai River but had no apparent effect on the Susitna escapement sonar count. Increasing uncertainty with the Susitna escapement assessment prompted ADF&G to initiate a 3-year study in 2006. The study utilized a DIDSON system, weir counts and a mark-recapture program to compare with the Bendix sonar counts.

In 2009 ADF&G released a special report because the study determined that the errors with the sonar counts were so significant. (ADF&G, FMS 09-01) The report documented that both the Bendix and DIDSON were grossly underestimating the number of sockeye salmon returning to the Susitna system.

The study results indicated that the Bendix sonar count (dating back to 1981) was biased low by more than 100 percent. From 1981 through 2008 escapement goals were being exceeded by an average of more than 100 percent, some years the goals were exceeded by 300-400 percent or more. More recent data indicates that trend continued until at least 2011. A reasonable person would think that, once this error was discovered, both ADF&G and the Board of Fisheries would revise the management plans that were based on this faulty data, but they did not and still have not.

During the decades that time and area restrictions were placed on the drift fleet to conserve northern sockeye stocks, no studies were ever done and no evidence or data was ever generated to show that the restrictions had any effect on escapements. What we have learned from the use of mandatory restrictions is that they prevent fishery managers from reacting to real-time information during the season and interfere with their ability to manage the whole fishery. Harvest opportunity has been lost due to the restrictions; not only the millions of sockeye that exceeded escapement goals in the Susitna, but also millions of sockeye that exceeded escapement goals in other Cook Inlet systems due to mandatory restrictions that were based on the faulty sonar data and flawed assumptions.

When you hear someone say the commercial fisheries are catching all the fish, it’s not any more valid today than it was twenty years ago. Those statements reflect an old paradigm that has been proven wrong. It’s not true for sockeye, kings or coho. The drift fleet harvest of Susitna sockeye is about 35-40% of the run, their harvest of king salmon is about zero percent. In an extensive mark and recapture study, ADF&G found that commercial fisheries harvested less than 6% of coho returning to the Susitna and Little Su Rivers. (ADF&G, RIR 2AO3-20) The commercial harvest of pinks and chums range from 2-6% of the run, which leaves a huge un-harvested surplus of these stocks.

The decades-long fixation on blaming the saltwater harvest of salmon for the alleged poor returns to the Susitna system distracted attention from the real and growing threats to salmon populations in the Valley.

Recent research has clearly defined the factors that are limiting salmon production in the Mat-Su: impaired/polluted water bodies; the introduced and now abundant invasive Northern Pike populations; disease and parasite occurrences; beaver dams blocking salmon passage; warm water temperatures that are lethal to most salmon populations; improperly installed road culverts that block salmon movements; unregulated habitat destruction due to 4x4’s, ATVs and air boats; and known poaching occurrences.

At least 14 of the original 24 sockeye-producing lakes studied in 1989 now contain invasive Northern Pike. Eight of those lakes with pike no longer produce salmon or trout; six more lakes with pike have severely reduced production. Shell Lake is a well-documented example. In 2006 Shell Lake had nearly 70,000 sockeye salmon return to spawn, by 2012 the salmon run had nearly collapsed due to pike predation and disease. The Cook Inlet Aquaculture Association, with funding from commercial fishermen, took eggs from the remaining salmon, incubated and reared them at their Trail Lakes Hatchery. In 2014 about 80,000 smolts from this hatch were released back into Shell Lake. Only about 20,000 of these smolts made it out of the lake and downstream towards the ocean. The other 60,000 smolts were consumed by the Northern pike in the lake within a few weeks.

Although much of the research has been focused on sockeye production, coho and kings are affected in much the same way, as they all spend a year or more in freshwater. Alexander Lake and Creek had had its king run virtually eliminated by pike. This led to a complete closure of the sport fishery, a loss of 26,000 angler days per year and the closure of 8 sportfishing lodges, impacts to associated guide businesses and float plane charter operations.

The Board of Fisheries and ADF&G need to focus their efforts on the cause of declining salmon runs, not just the effects. A new action plan should be developed that will help stabilize salmon production in systems that are still functioning, work towards eliminating pike from other systems, set goals for removal of migration impedances and develop a rehabilitation and stocking program.

Until ADF&G, the Board of Fisheries and the Mat-Su Borough start eradicating the pike infestation in a significant way the salmon runs in the Mat-Su Basin will never recover.

Erik Huebsch is the Vice President of the UCIDA.