Federal fishery biologists expect only 30-million pink salmon, or humpies, will be harvested in Southeast Alaska 2016. That’s well short of 2015’s disappointing harvest of 34 million fish and 2013’s record catch of 95-million pinks.
As part of a post mortem on last year’s wonky salmon runs, KTOO’s Matt Miller visited a weir near Juneau that has been recording salmon going out and coming back earlier and earlier for the last 35 years.
Last year’s pink salmon runs in Southeast Alaska weren’t horrible, but they weren’t great either. It actually made a big difference where the fish returned in the Panhandle.
“Northern Southeast turned out good, above average,” said Joe Orsi, a research fisheries biologist at NOAA’s Ted Stevens Marine Research Institute. “But southern Southeast just tanked.”
Orsi speculated that warm sea surface temperatures may be responsible for this year’s high survival rates or larger fish size. But those results were not universal for all Southeast Alaska pink runs.
“Basically it’s about a million or so fish higher than the ten year average in northern Southeast,” said Orsi. “But southern Southeast Alaska, it’s been like ten million fish below the ten year average. So, there appears to be a split in the production and survival of pink salmon about in the middle of Southeast Alaska.”
Prince William Sound and Kodiak pink runs also came in strong.
But why? For now, Orsi said they can only speculate on the reasons.
“I know they had a lot of flooding events last winter down there,” Orsi said. “That’s a possibility. There could’ve been a mismatch of the fish entering the marine environment and the timing of the zooplankton down there. There could’ve been an assortment of predators or competitors that came up with the warm Blob that may have impacted the juvenile salmon. There’s just a lot of unknowns.”
Pink salmon returning to Southeast Alaska last year were the children of 2013’s big return that formed the basis for that season’s record 95-million fish harvest.
Orsi earlier predicted that 54-million pinks would be harvested last season. Going off of his numbers, the Alaska Department of Fish and Game forecasted a range of 37- to 58-million fish that would be taken by all gear types.
But only about 34 million were caught.
Orsi concededed he was way off
“ Last year, we predicted a fairly good pink salmon return to Southeast Alaska,” said Orsi. “I kind of have to face the music. We didn’t get that strong return this year.”
It’s still unclear whether a persistent warm water anomaly nicknamed The Blob or a developing El Nino had any impact on those runs.
Auke Creek is just one example of how some streams in northern Southeast had better returns than other streams further south. The Auke Creek Weir and Hatchery is a small, federally-operated facility tucked away in the woods in the 15-hundred feet between Auke Lake and Auke Bay.
John Joyce, one of Orsi’s colleagues, is a research fisheries biologist at NOAA’s Ted Stevens Marine Research Institute who spends a lot of his time at the weir. He says local geography and the relatively low drainage area are big factors in the health of the system.
“Flow is very important.” Joyce said.
A low snowpack in the Auke Lake drainage melted early in March and April last year. That was followed by a very dry May and then heavy rain by July.
“So, all of that affects not only the flow in the creek, but also the temperature,” said Joyce. “Temperature and flow are really important factors for fish that migrate, for juveniles and adults.”
Joyce used words like “phenomenal” and “incredible” to describe over 24-thousand big pinks that returned to Auke Creek this summer. That’s over a 51 percent marine survival rate for the 47-thousand juvenile salmon that passed out of Auke Creek and into the ocean previous year. Normal survival rates for returning salmon range from a tenth of one percent to ten percent.
The Auke Creek facility is unique because biologists have data on stream flow and water temperatures that correspond with 35 years of continuously counting salmon.
Joyce said they noticed silver returns have been compressed into largely a two-week period while pink runs have trended two weeks earlier over the last three decades.
“It’s substantial,” said Joyce. “And it has ecological implications, too, because these juveniles have adapted to certain timing to enter the ocean. Well, that adaption to timing could be differently influenced in fresh water than salt water. So, you could potentially have a mismatch where they’re going faster in fresh water but the ocean is not ready for them.
Joyce said their research into migratory behavior and ocean survival has implications for resource management.
“If you have salmon that used to run over a month and you could access them and now they’re running over two weeks, it affects your ability to harvest, it affects predators’ ability to kill,” said Joyce. “So, it does have ecological impacts in terms of the systems, too.”
Joyce says they’re collaborating with the University of Alaska of Southeast which is using their 35-year data sets in their research to determine how climate change is influencing migratory behavior, marine survival and productivity.