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Researcher lays out three major possibilities for Alaska king salmon crash

Suzanna Caldwell

On Monday in Anchorage at the first day of the Alaska Marine Science Symposium, where hundreds of scientists gathered to talk ocean science, it was appropriate that the day start with a quote from Martin Luther King, Jr., given the holiday.

We may have all come on different ships, but we're in the same boat now.”

Fitting for a symposium dedicated to sharing ocean research in the Bering Sea, Arctic Ocean and Gulf of Alaska. Keynotes from the day focused on several major issues all Alaska oceans are struggling with -- acidification, tsunami debris and the highest-profile of all: Chinook salmon stocks in decline.

Alaskans have taken particular notice of chinook salmon runs lately because returning numbers of those fish have been dropping steadily in recent years. But 2012 hit the state especially hard -- with multiple rivers and regions across the state seeing some of the lowest returns ever, forcing Alaska Fish and Game officials to close or severely limit salmon fishing around the state, including on some of the state's most iconic rivers.

In Western Alaska, Native subsistence fishermen protested the closures, saying they threatened their livelihoods. They were ticketed, and since have begun fighting the citations on grounds of Yup'ik religious and cultural freedom. In Southcentral Alaska, commercial fishermen and sport fishermen dueled over who shared the burden of conservation -- leaving both groups beached for most of the summer.

Where did all the king salmon go?

Ed Farley, of NOAA's Alaska Fisheries Science Center Auke Bay Laboratory in Juneau, laid out some of the reasons why scientists think chinook stocks have been in precipitous decline. But like other scientists who met this fall for a symposium dedicated solely to the issue of Chinooks, the answer remained the same -- no one really knows, and only one thing can help moving forward -- more money to study the scientific reason for the decline.

“To know anything, we have to be out there on research vessels or talking to commercial fisheries to get an idea of what's going on with their marine environment,” Farley said.

Although there is no shortage of possible reasons, Farley dissected the three major hypotheses regarding the decline:

  • Critical size and period: Juvenile salmon are most sensitive to predation when they first leave freshwater streams and head for the ocean, where they spend one to six years growing before returning to their home stream to spawn. Farley noted that climate change could be impacting the Chinook food sources, leading to smaller fish that face greater risks from other marine predators when they first enter the ocean environment.

  • Match/mismatch: The warming terrestrial environment is impacting the migration and food sources of king salmon. Rivers are having earlier large discharges to the ocean, and those outputs have a direct correlation to when chinook salmon head for the ocean. If they head to the marine environment earlier, when they are smaller, they are less likely to survive. Another complication of the warming weather? Sea ice, which in some places can create water with a higher salinity that stresses the chinook, who need brackish water to successfully survive the transition from fresh to salt water.

  • Declining size at age: Chinook salmon seem to be decreasing in size, although scientists aren't sure why. Farley suggested that a human component might be at play, since most fishermen, especially sport fishermen, are keen on catching the largest fish possible.

“We all want to catch the big Chinook,” he said. “It could lead to a reduction in the genetic trait of big fish coming back to spawn.”

Farley said that data collected from the Juneau Chinook Salmon Derby showed the top 30 fish averaged 37 pounds in 1997. By 2007 that weight had fallen to 27.

Bigger fish can handle the strenuous journey it takes to fight strong currents and tall waterfalls to return to spawning grounds, giving smaller fish less access to spawning grounds. Farley said that smaller size also equates to a serious difference in the amount of eggs a female produces. Fewer eggs, fewer kings.

Big crash, bigger budgets?

Farley, like many other scientists, suggested that the key to learning the mysteries behind the chinook salmon decline are in the science, which needs continued stable funding. Both Alaska Senators Lisa Murkowski and Mark Begich, in prepared video remarks to the symposium attendees, noted they would both continue to fight for that funding, despite a challenging fiscal climate.

Alaska fisheries have not fared well in terms of federal funding as of late. $150 million for fisheries disasters was stripped from the final version of the Hurricane Sandy relief bill after it faced criticism from other Washington lawmakers. Begich, in particular, has said he will continue to fight on Capitol Hill for disaster relief funding for fishermen impacted by the dismal 2012 salmon runs.

However, in Alaska, things are looking better. In November, Gov. Sean Parnell said he would include $10 million in his 2014 fiscal budget for a Chinook salmon research initiative. If approved by the Legislature, that funding will be added to the $14 million Alaska Fish and Game currently spends annually on chinook salmon research.

The symposium continues through Friday.

Contact Suzanna Caldwell at suzanna@(at)alaskadispatch.com