July 25, 2013 | Volume 43, Number 29

King run numbers lowest in 20 years

Mark-recapture surveys in the lower Chilkat River suggest the local king salmon return may be the weakest in 20 years, according to Brian Elliott, assistant area fisheries biologist for the Sport Fish Division of Fish and Game.

Through Sunday, the state’s drift nets had caught only 31 mature kings. As the survey typically counts 3.9 percent of the total run and 98 percent of the run typically has passed through the lower river by the third week in July, the state is projecting less than 1,000 kings will return to spawn, Elliott said.

King salmon escapement to Chilkat River tributaries has failed to reach the minimum goal of 1,850 spawners during three of the past six years. Fish and Game forecast a weak king return at the start of the season and has closed some sport fishing and subsistence fishing areas on the river through July to protect returning fish.

“We’re doing what we can to get (kings) up to the spawning grounds. It’s disappointing. It’s not fun for us to manage declining runs,” Elliott said.

Typically, 134 kings have been caught in the lower river by July 21. The lowest previous lower-river count was a total of 65 kings, caught in 2007. In that year, 1,442 mature kings returned to spawn.

Elliott said hot weather in June that created prolonged high-water flows in the river may have hurt catches, but the state has generally found in previous years that such high-water events haven’t made a significant dent in its sample fishery.

Fish wheels along the Chilkat also have seen diminished catches this year, he said.

Most of the kings returning this year were spawned in 2007 and 2008, Elliott said. While the number of spawners in 2007 was depressed, 2,833 mature returners in 2008 put that return in a good escapement range, Elliott said.

“My hunch is we’re looking at poor marine survival during those brood years,” Elliott said. “Fresh water rearing doesn’t seem to be a problem. We’ve estimated robust smolt populations leaving the Chilkat River.”

Ed Jones, a coordinator for Fish and Game, said king populations throughout Southeast have tanked in the past few years, with fewer than 1 percent of smolt surviving after heading into salt water compared to a normal survival rate of 4 or 5 percent. It’s part of a statewide trend extending from southern British Columbia to the Yukon River. “These fish are going out and dying and we don’t know the reason.”

The drop is a “pretty severe hit” but higher numbers of immature fish showing up indicate the trend appears to be turning around, Jones said. King numbers plummeted in the Pacific Northwest a few years ago, prompting concerns about the fate of runs there, but numbers bounced back.

While king salmon runs may fluctuate in strength, what’s worrisome are the peaks and valleys in the recent numbers, Jones said. “It’s alarming that we’re seeing very high highs and very low lows. The recent numbers aren’t a little below average. They’re just not there. That’s something we haven’t seen in the past three decades.”

King escapements were low in the 1970s, but “nowhere near the across-the-board levels that we’re seeing right now,” Jones said.

King salmon smolt from the Chilkat River rear in the Inside Passage, while smolt from other Southeast rivers – including the Alsek, Taku, Stikine and Situk – go as far as the Bering Sea to grow up. However, there’s no discernible difference in the survival rates of fish that rear in Southeast and ones that go elsewhere.

That and other factors lead Jones to believe the juvenile fish are dying in their first few months in salt water. “We have data to suggest that, but to prove it is really hard,” Jones said.

The state’s most comprehensive information on king salmon is on the runs in Southeast, with data going back to the early 1970s, he said.