The initial period after ocean entry for
Columbia River basin juvenile salmon and steelhead is when most of the
mortality occurs during their lives at sea, so ocean conditions – temperatures and
nutrient supplies – during that period are critical to how many of the fish
will return to the river as adults one to three years later.
The path the fish take after they enter the
ocean makes a difference, according Laurie Weitkamp of NOAA Fisheries’
Northwest Fisheries Science Center, Newport, OR Field Station, especially
lately with the “strange” ocean conditions.
Not all salmonids are the same, she said, and
collectively that determines their marine survival.
The fish enter at different sizes, ages and
times; they go to different areas after they enter the ocean; they even eat
different food; and return at different ages and at different times.
For their first summer in the ocean spring
chinook, chum, sockeye and some coho head north along the coast into the Gulf
of Alaska. Some of those chinook have been caught as far north as the Bering
Sea, Weitkamp said at this week’s Northwest Power and Conservation Council
meeting, Jan. 10.
Fall chinook and some coho remain in more
local waters off the Oregon and Washington coastlines. And, steelhead appear to
rapidly head straight out to sea, sometimes traveling nearly to Russia.
Weitkamp was at the meeting to brief the
Council on ocean conditions and how those conditions impact smolt survival and
Weitkamp’s presentation, attached to a Jan. 3
Council memorandum, is at https://www.nwcouncil.org/media/7491479/3.pdf
As adults on their return journey to the
Columbia River, fall chinook, chum and sockeye move south along the continental
coastline; coho come in from Oregon and Washington coastal areas; and steelhead
and spring chinook move rapidly from their offshore positions towards the
Why is this important, she asked? Because,
once at sea, ocean conditions, harvest and predators impact survival as the
juveniles grow to adults.
As for ocean conditions, the “Blob” has had a
huge impact on sea surface temperatures and food along the northern coastlines
and “we’re still seeing what we are calling the ‘hangover’ effect.’” That began
in 2013 to 2014 with a “ridiculously resilient” high pressure ridge, similar to
what we had for shorter period this past December, Weitkamp said.
Generally, nutrient rich water is brought to
the surface by storms and at some time there are heat transfers to the ocean’s
depths and from the ocean to the atmosphere.
But poor ocean conditions began with warm, low
nutrient waters and a “big mess of water that didn’t get cooled because we
didn’t have many storms,” she said. 2016 brought one of the three strongest El
Nino’s in recent history, but by Dec. 17 this year, there has been a change to
La Nina conditions that began the week of Nov. 6 with cold water at the
“If you look at forecasts, we’re getting back
to more normal conditions, although there is still some warm water to the
north,” Weitkamp said. “In 2018, the cooler coastal waters should be good for
salmon entering the ocean.”
The bottom line is that there was a huge
biological response to the warm water, she said, including the arrival in the
north of tropical species beginning in 2015. Demoic acid closed crab and clam
fisheries from California to Alaska. There were dramatic changes to the food
web and young chinook and coho salmon were very skinny.
2015 was also the year of starving sea lion
pups in California, followed by a dramatic increase in adult California sea
lions in the Columbia River. “We also saw some female California sea lions as
well as pups in the river,” Weitkamp said.
In 2016, red pelagic crabs were found in
Oregon (the previous northern limit for these crabs was Mendocino, California),
anchovies invaded the Salish Sea and fishery closures due to demoic acid
Swordfish were sited off Vancouver Island in 2017;
cod declined in Alaska, resulting in a scaling back of the fishery in that
state, and pyrosome populations (a warm water species) exploded and continue to
wash up on beaches. Crab fishing has yet to open this year (in Oregon
commercial crabbing opens Jan. 15). The good news has been the high Pacific
lamprey counts at Columbia River dams.
As for salmon and steelhead, in 2015 there was
a low abundance of juvenile spring chinook and coho. Fraser River and Salish
Sea coho saw a similar decline in abundance.
“We know that when you have low abundance of
juveniles, you will have low adult returns,” she said, pointing to a low run of
coho in 2015. In fact, Columbia River and coastal coho returns were some of the
lowest since the 1990s.
Alaska pink salmon had the lowest return in
memory in 2016 and Fraser sockeye returns were the lowest on record, but chum
returns to the Fraser River were the highest in 20 years. There were high chum
returns, as well, in Washington and Oregon.
As conditions were improving in 2017, Alaska
saw the highest chum harvest ever, along with high pink and sockeye returns,
yet there were fishery closures for chinook in British Columbia, Washington and
Oregon. Steelhead returns to the Oregon coast were the lowest ever and the
Klamath River chinook fishery was closed.
“It seems like we’re doing a pretty good job
of getting the juvenile fish to Bonneville Dam, but we’re losing them in the
ocean,” said Idaho Council member Bill Booth. “And there’s also predation and fishing in Alaska” to consider.
When evaluating the smolt to adult returns to
Bonneville, “we should consider all the hits to the fish – predation, harvest
and other factors. We send out 250 million smolts into the ocean and only 2
million come back,” he continued. “I’d like to see NOAA take a more broad
approach and consider harvest and predation.”
Looking at it from a slightly different angle,
Weitkamp instead suggested considering changes in fresh water that could give
juveniles a survival advantage in the ocean.
“Willamette River chinook juveniles, for
example, leave the river early and grow quickly in the estuary and ocean. The
smaller you are, the more prone to predation. If you can get a wild fish to be
5 millimeters larger when they enter the ocean, how much would that count in
their survival?” she asked.
In her summary, Weitkamp said that the warm
ocean conditions present since 2014 continue across large parts of the North
Pacific and we should expect the biological effects of a warm ocean to continue
for several more years. However, on the positive side, the cooler coastal
waters forecast for spring 2018 should be good for young salmon entering the
--CBB, September 29, 2017, “Warmer Northwest
Waters Have Fish Moving North, Spawning Earlier, Longer Off Pacific Northwest,”
--CBB, July 14, 2017, “Ocean Conditions, Sea
Lions Faulted For Low Willamette Steelhead Return; Only 822 Wild Steelhead,” http://www.cbbulletin.com/439268.aspx
--CBB, February 17, 2017, “New Research
Details Forage Fish Stocks Boom-Bust Cycles For Centuries,” http://www.cbbulletin.com/438350.aspx
--CBB, January 19, 2017, “Research: El Nino,
Pacific Decadal Oscillation Correlates With Domoic Acid Shellfish Toxicity,” http://www.cbbulletin.com/438200.aspx
--CBB, October 7, 2016, “Study Connects
Massive West Coast Toxic Algal Bloom In 2015 To Unusually Warm Ocean