Chilkat Valley News - Serving Haines and Klukwan, Alaska since 1966

Ocean-going king smolts dwindle

 

February 28, 2019



Chilkat king smolt that left the river drainage in 2014 was the lowest on record, according to Alaska Department of Fish and Game estimates, a dismal sign for a fish population already on the decline.

Between 1999 and 2013, an average of 185,000 smolt left the Chilkat drainage for the ocean. In 2014, biologists estimated only 64,000 smolt from brood year 2012 survived their rearing habitat before leaving for the ocean.

Kings return at different age classes, although the bulk of the run in the past several years consist of five-year-olds. The smolt that left for the ocean in 2014 contributed to the four-, five- and six-year old fish that returned in 2016, 2017 and 2018—run years that all failed to meet Fish and Game’s escapement goals required to sustain a healthy run.

Fish and game biologist Brian Elliott said the low numbers of spring smolt leaving the drainage in 2014 don’t bode well for future returns.

“There’s not much to really hang your hat on recovery,” Elliott said. “We’re at a survival rate of less than 2 percent. You can overcome that with bigger numbers leaving your drainage, but we’re not seeing that anymore. We really need that uptick especially given the fact that our smolt population seems to be decreasing also. This recovery is going to be an inch by inch process. I’m not seeing any quick fixes for this population to recover.”

If 2 percent of those fish survive the marine environment, 1,280 fish would return dispersed across a three-year period. If one percent survives, 640 fish would return across a three-year period. Those numbers reflect total king survival including four-year-old fish. Only five- and six-year-old fish count toward the escapement goal.

“The only good return in the last several years was in 2015, and that run was carried by 5-year olds from brood year 2010. That age class just didn’t come back as six-year olds,” Elliott said. “So then we fell right back down and now we’re in the position we’re in.”

Six-year-old kings have declined at an alarming rate, and represent about 10 percent of returning fish. Larger and older kings produce more eggs and can dig redds in river bottom material that smaller fish aren’t strong enough to.

Kings lay their eggs in late summer and the alevins hatch the following spring. They then spend a full year in the drainage including over the winter months. Winter conditions impact rearing fish. The past two winters have been defined by cold temperatures and little snowfall to insulate the rivers from freezing too deeply.

“Winters where we get these high pressure systems with the north wind pounding every day, it literally freezes some of these off-channel areas where Chinook like to rear in the winter,” Elliott said. “That’s a big problem.”

Elliott said the smolt they did find were healthy, and that the lack of competition for food could produce strong fish and increase their survival odds. On average, 36 percent of smolt survive their overwinter Chilkat drainage freshwater habitat. While brood year 2012 was rearing, Elliott estimated only 21 percent survived their overwinter habitat.

Elliott projected about 1,000 fish will return to the drainage this summer, well below the 1,750 escapement goal. Last summer only 873 kings returned to the drainage, according to Fish and Game estimates. That year’s projected run forecast was 1,030. It was the sixth time the run failed in the past seven years.

For the first time in recent years, Fish and Game has projected runs to fail across all five river systems for which forecasts are produced, including the Stikine and Taku. “We were expecting bad and that’s exactly what we got,” Elliott said.

The Alaska Board of Fisheries last year labeled Chilkat kings, along with kings in the King Salmon and Unuk rivers as “stocks of concern,” because runs have continuously failed to meet escapement goals. That designation came with a host of increased commercial, sport and subsistence fishing restrictions across Southeast.

 
 

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