A commercial salmon drift gillnetter at work in the waters of Cook Inlet/Alaska Department of Fish and Game photo

Cook Inlet commercial fishermen who forced national intervention in the management of salmon bound for the Kenai, Kasilof, Susitna and other Southcentral Alaska rivers appear as if they might have sued themselves into their worst nightmare.

What the fishermen dreamed of winning when they went into the U.S. District Court for Alaska was federal management to boost catches in the offshore waters of Cook Inlet at the expense of personal-use dipnetters and anglers fishing the rivers of the region that surrounds the state’s largest city.

They got the federal management. The rest of the dream remains in limbo, and there are suggests it might not turn out so well.

A consultant to the North Pacific Fishery Management Council (NPFMC) in December shot some big holes in one argument for why commercial drifters need to kill more salmon offshore in federal waters.

Curry Cunningham, a quantitative ecologist at the University of Alaska Fairbanks, concluded commercial fishermen’s claims of Kenai over-escapment are a bunch of hooey, according to the minutes of the Council’s Cook Inlet Salmon Committee.

For years, commercial fishermen have hyped fears of too many salmon in the Kenai. The biggest salmon producer in the region, the Kenai also supports the state’s largest sport fishery and attracts tens of thousands of resident, personal-use dipnetters looking to fill their freezers with salmon for the winter.

Given all the interests competing for Kenai fish, the river long ago became the tail that shakes the Inlet dog.

On average over the last five years, about 1.2 million sockeyes per year have escaped commercial fishermen and made it into the Kenai. Alaska Department of Fish and Game biologists have concluded the river could make do with as few as 700,000 per year – a full half-million less.

Too many spawners

Watching all those fish get away, the thinking of the 1,000 or so commercial fishermen active in the Inlet has long gone like this:

State biologists trying to protect runs of Susitna sockeye and coho salmon – fish favored by anglers in the Matanuska-Susitna Borough – are putting too many restrictions on the mixed-stock commercial fishery in the Inlet – which reduces the commercial harvest, and as a result, so many salmon make it into the Kenai that future runs suffer.

The latter conclusion is based on an old, old fisheries model called the “Ricker curve,” which dates back to work done by the late Canadian biologist Bill Ricker in 1954. 

Ricker came up with a mathematical model for managing salmon returns. Presented as a graph, it is basically bell-shaped with a long tail. For years, it drove fisheries management with managers believing that the ideal was to manage salmon for the peak of the bell where rivers theoretically returned the maximum number of salmon per spawning fish.

Science since then has shown fisheries aren’t quit this simple and questioned the accuracy of the model. As new models have emerged, the point at which it can be concluded too many fish have entered a river has shifted. In the process, the doomsday black suit of the bogeyman of over-escapement has donned a more business-like suit of gray.

Enter Cunningham:

“Dr. Curry Cunningham provided a presentation on alternative stock-recruitment models for estimating management reference points (stock condition and maximum sustained yield) and hypothesis testing of the degree to which overcompensation is evident from the Kenai and Kasilof river data, using well-established statistical methodologies that are generally applicable to salmon populations,” the NPFMC summary says.

“With respect to overcompensation. Dr. Cunningham indicated that the Kenai River data supported a compensatory, or Beverton-Holt type relationship with little potential for overcompensation, while the relationship in the Kasilof River was less obvious, but generally did not
support the overcompensation hypothesis.”

The NPFMC is heavy on jargon. It is not a layman-friendly public entity.

But the key words in the summary are these: “little potential for overcompensation.”

“Overcompensation” is defined by the Alaska Department of Fish and Game as “declining productivity at high escapement levels,” ie. over-escapement. 

Salmon simplified

Short version?

Claims of sockeye over-escapement in the Kenai depleting future runs are bunk – at least at current escapement levels. The conclusion is not out of line with the state’s last review of Kenai escapement in 2014. It noted the large degree of variability in years of large returns.

“Escapements below 400,000 salmon never produced yields exceeding 948,000 (total run size),” authors Lowell Fair and Mark Willette wrote. “The highest yields originated from escapements of 755,000, 792,000, and 1,983,000 sockeye salmon (brood years 1982, 1983, and 1987). When
escapements exceeded 900,000, yields were highly variable, ranging from 513,000 to 8,396,000.”

“Yields from the 2005 and 2006 year classes, both having large escapements (1.6 million in 2005 and 1.9 mllion in 2006), were above average. This pattern of greater than average yield from consecutive large escapements is inconsistent with the brood interaction observed in brood years 1987–1990,” which at the time suggested over-escapement.

The 2005 run produced a future return of 4.6 million sockeye. The 2006 run produced a future return of 4.8 million. But the state biologists warned such high returns off big escapements cannot be counted upon.

“The committee recommended that the Kenai River late-run sockeye salmon sustainable escapement goal (SEG) be kept at 700,000–1,200,000 spawners,” they wrote. “This range approximately represents the escapement that, on
average, will produce 90 to 100 percent of maximum-sustained yield. We prefer using the 90 to 100 percent range for an SEG because it results in a broader interval with the highest predicted yield near its center.”

At that level, the state’s minimum in-river goal for sockeye is 900,000 – the 700,000 fish for escapement and 200,000 for the sport fishery. The minimum does go up if runs are strong, mainly because it floats to try to  maximize the commercial catch.

The state report written by employees of Fish and Game’s Division of Commercial Fisheries was careful to avoid the word over-escapement. It appears only once in the form of a Kenai sockeye over-escapement study listed in the three pages of references at the end of the document.

But then again, the over-escapement issue might be less important on the state level than on the federal level where fishery managers, as the NPFMC report notes, operate under a “primary obligation…to prevent overfishing.”

In other words, getting adequate numbers of spawners into the streams at the head of Cook Inlet, trumps any issue with over-escapement on the Kenai up until the latter becomes damaging to the resource.

None of this seems to have gone over well with the salmon committee, which wanted to talk about “underfishing” instead of overfishing but was rebuffed.

“…Some Committee members objected to the presentation of Appendix 1 stating that the Magnuson-Stevens Act requires that it first be vetted by the scientific and statistical committee,” the report said.  “It was pointed out that this was an informational presentation, that it was being provided because it is relevant to stakeholder comments about over-escapement of salmon that the SSC will review….

“(At the end of the meeting), some Committee members repeated their objection to the information in Appendix 1 to the discussion paper. Council staff agreed to include this position in the report, but stated that it would not be presented as a recommendation or a reflection of Committee consensus.”

The so-called “stakeholder” committee is composed of five Cook Inlet commercial fishermen and Alaska Board of Fisheries member John Jensen, a commercial fisherman from Petersburg in Southeast Alaska. There are no sport fishermen or personal-use dipnetters on the committee. The Council decided they didn’t have a role to play since they don’t fish in the federal waters of Inlet; they only catch the fish that escape the Inlet’s driftnet fleet and make it into state waters.

But the NPFMC has vowed to protect the interests of other Cook Inlet salmon harvesters and to ensure responsible conservation in federal waters.

There has even been mention of putting observers – standard in some other federal fisheries – aboard Cook Inlet drift boats to monitor catches. Such a plan is sure to go over as even more of a lead ballon than the dismissal of the idea that big sockeye returns to the Kenai result in run-wrecking over-escapement.