The Alaska Department of Fish and Game is recommending putting a big-fish goal in place for Kenai River king salmon.
In a Monday memo attached to the schedule for the Board of Fisheries’ upcoming Lower Cook Inlet meeting, which is set for Nov. 30–Dec. 3 in Homer, Fish and Game research biologists recommend implementing a big-fish goal for both the early and late runs of king salmon to the escapement goals on the river.
Under the recommendations, Fish and Game managers would have to achieve a sonar-based goal specifically for king salmon 33.3 inches or longer from mid-eye to fork. For early-run king salmon, the goal would be set at 2,800–5,600, and for late-run kings it would be set at 13,500–27,000, according to the memo. Big fish goals set a minimum number of fish that must meet a particular size requirement, not counting those that are smaller.
The current escapement goal for early-run king salmon is 3,800–8,500 fish of any size, and the late-run has a goal of 15,000–30,000 fish of any size. Both goals were adopted in 2013, according to the memo.
King salmon stocks in stream systems around the state have been declining both in size and numbers in recent years, including on the Kenai River. As previously reported by the Clarion, size decline has concerned and puzzled researchers, who have linked it to more young fish returning as the population of older age classes decreases. Older, larger fish have been shown to be more fertile as well as more desirable for fishermen.
The 33.3-inch length was selected because sockeye don’t typically reach that size, making it easier to distinguish kings from sockeye on the sonar images, said Tim McKinley, the regional research coordinator for the Division of Sport Fish in Anchorage. An Oct. 3 escapement goal memo submitted to the Board of Fisheries for a worksession held in Soldotna states that the finalized recommendations will be presented at the Upper Cook Inlet meeting in Anchorage in Feburary 2017.
“In the Kenai River, fish of this size can be assessed more simply, accurately and timely,” the Oct. 3 memo states.
Fish and Game counts king salmon in the Kenai River using a sonar system supplemented by data from a test net. The sonar takes ultrasound images of fish passing through a particular section of the river in front of the sensor, and fish biologists can count the fish on the image transmitted to their computer screens.
There has been controversy over the accuracy of the sonar counts over the years. Fish and Game replaced its older Kenai River sonar systems in 2009 with the DIDSON system, which was again replaced in 2015 because of concerns about accuracy. The current system, the ARIS, counts salmon at river mile 14. Fish and Game has had concerns over the years about the accuracy of sonars because it’s difficult to distinguish fish species and sometimes river conditions get in the way.
Fish managers in other areas of the state have already begun using big-fish goals for kings. Ten of Southeast Alaska’s 11 king salmon goals are big-fish only goals, according to a 2014 Fish and Game Southeast Alaska escapement goal memo.
A committee of 35 Fish and Game staff from the various divisions of the department worked on the updates to the escapement goals, according to the Oct. 3 memo. The report with the full rationale is still being prepared before the meeting in February, according to the memo.
Reach Elizabeth Earl at firstname.lastname@example.org.