Getting a better king count

Fish and Game research projects to better gauge salmon runs

Posted: Friday, February 10, 2006

The Alaska Department of Fish and Game is gearing up for a growth spurt in fisheries research projects this summer, including a study that is gauging the first estimates of late-run king salmon numbers in the Kasilof River.

The projects will mean more work for fish researchers at Fish and Game, but the opportunity to learn more about local fisheries is welcomed, said Tim McKinley, a research biologist for the sport fish division of Fish and Game.

“These fish are valuable, extremely valuable,” he said. “(And) the better and finer tuned we can have our management the more likely we are to have healthy runs.”

McKinley mentioned the king salmon counting project in the Kasilof River and a Kenai River king salmon genetic sampling project as some of the highlights.

“The Kasilof project is exciting because we haven’t had a lot of information on Kasilof kings,” he said.

Although king salmon in the Kenai River have been researched for approximately 30 years, Fish and Game knows little about the late king salmon that spawn in the Kasilof River.

“Almost everything we learn about them is new,” he said.

One of the reasons that Fish and Game has collected little research data about late run Kasilof River king salmon is that the Kasilof River is not conducive to counting with sonar.

“There are some difficulties in counting kings in the Kenai, and they’re even worse in the Kasilof,” he said.

The river’s late run king salmon are particularly difficult to count since, unlike the river’s early king salmon run, the fish do not leave the cloudy glacial water of the Kasilof River to spawn in one of the river’s clearer tributaries, said Adam Reimer, a Fish and Game fisheries biologist.

“The (Kasilof River’s) water is not clear so it’s hard to estimate their abundance,” he said.

Although Fish and Game has accumulated decades of research on king salmon in the Kenai River, McKinley said Kenai River king salmon research continues to excite him because current research can focus on more detailed information and test the accuracy of information collected in the past.

The Kenai River king salmon genetic sampling project will offer Fish and Game a more accurate picture of when the early and late king salmon runs begin and end, information vital to obtaining escapement goals, said Robert Begich, a Fish and Game sport fish research biologist.

Early run king salmon and late-run king salmon are genetically distinct and Fish and Game need to be able to identify which fish belong to the early run and which fish belong to late run because escapement goals are different for each.

Escapement goals for the early run are between 5,300 and 9,000 fish, whereas escapement goals for late salmon runs are between 17,800 and 35,700. For every adult king salmon that escapes the fisheries and predators to spawn up river, approximately three new salmon reach adulthood.

Distinguishing early run fish from late-run fish is can be difficult without being able to identify them genetically since some early salmon are tardy and some late salmon enter rivers prematurely, McKinley said.

Genetic samples have been taken from Kenai River king salmon before, but unlike previous samples these samples will be taken from salmon in spawning grounds rather than from various points on the river and will reveal more accurate data on king salmon populations, including sub populations within early and late runs, Begich said.

McKinley likened genetic sampling of salmon at various points of the river to standing at a school entrance and trying to count the number of children per grade range based on when they walk into the school.

If school children in first through third grade begin class at 8 a.m. and fourth- through sixth-graders begin class at 8:30 a.m., that does not necessarily mean every child that walks into the school door after 8 a.m. is in fourth through sixth grade, he said.

Sampling at the salmon’s spawning grounds will avoid the confusion that can be created by stragglers and early arrivals, McKinley said.

“It’s almost like you go into the class and identify the kids,” he said.

In addition, the genetic king salmon project will contribute to the Pacific-wide push to create a database that genetically identifies all king salmon populations, entering the first Cook Inlet king salmon population to be recorded in the database, Begich said.

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