Ocean conditions for many fish species in the Pacific
Northwest, including chinook salmon, were greatly improved
in 2008 because of a huge cold-water influx that settled in
across much of the Pacific Ocean.Scientists who surveyed coastal waters from Newport, Ore., to LaPush, Wash., found the highest numbers of juvenile chinook salmon this year than they have seen in the 11 years that sampling has been done, which suggests that the Northwest could see a salmon boon once these fish mature and migrate back to their home rivers.
The increase may be traced to the Pacific Decadal Oscillation, a climate pattern that has shifted between cool and warm cycles in periods of 20 to 30 years. This year, the PDO was cooler than it has been since 1955, according to Bill Peterson, an NOAA-fisheries biologist at Oregon State University's Hatfield Marine Science Center, who is also affiliated with OSU's College of Oceanic and Atmospheric Sciences.
"We usually see cold water conditions for a few months once upwelling begins in late spring and early summer," Peterson stated in an OSU press release. "Since April of 2007, though, we've been in a constant 'summer-state' ocean condition, which is something we've never seen in more than 20 years of sampling. And we're not sure why."
This condition has fueled phytoplankton growth, which are rich in fat and provide food for small fish. These small fish in turn become food for salmon, lingcod and other marine life. Researchers have said that the seabirds are looking very well-fed as well.
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Pacific Ocean Conditions Optimal For Fish Survival In 2008
Oceanographers are witnessing some of the best survival conditions for sport fish ever recorded off the Pacific Northwest coast. A strong and sustained upwelling of colder water gets the credit. Correspondent Tom Banse reports.
Scientists don’t completely understand why the North Pacific basin oscillates between warm and cool phases, each lasting for years. What we do know is that the cool cycle is more favorable for fish survival, especially for growing salmon.
Oceanographer Bill Peterson of Newport says it’s become clear the cycle flipped last year. Cold currents and upwelling are stimulating the food chain near our shores.
Bill Peterson: “That’s certainly been the case. There’s been a lot of zooplankton and they feed a pretty concise stock of what is called forage fish -- things like anchovies, sardines, herring, and little smelts. Those fishes are the main prey for the salmon.”
Peterson can’t predict how long the favorable ocean conditions will last. He says it usually takes one or two years after the ocean turns cold for bumper salmon runs to show up in our rivers.
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Oregon ocean conditions best for fish in 50 years
by Michael Milstein, The Oregonian
A
copepod called Neocalanus cristatus, which is
rich in fats and has provided food for the
marine food chain off Oregon this year.After several years of poor ocean conditions that left birds starving and fish dwindling, this year brought a healthy influx of cold, nutrient-rich water along the Oregon Coast that likely represent the best year for fish in decades, scientists say.
Surveys along the coast from Newport north to LaPush, Wash., found more juvenile chinook salmon than they've seen in the 11 years the surveys have been done, researchers said.
That suggests that the Northwest could see a salmon boom once those fish mature and migrate back to their home rivers in the next few years.
That would represent a welcome contrast to the last few years.
The key to ocean productivity off the Oregon Coast is upwelling of deep, cold water that is rich in nutrients. The water typically nurtures rich marine ecosystems, but last year and in the few years before the upwelling has happened erratically and hasn't provided the nutrients essential to fish and other coastal life.
Scientists believe that the return to positive conditions may be connected with the Pacific Decadal Oscillation, a climate pattern that shifts between warm and cool cycles in periods of 20 to 30 years. This year, the pattern was cooler than it has been since 1955, said Bill Peterson, a NOAA-Fisheries biologist based in Newport who is also affiliated with Oregon State University's College of Oceanic and Atmospheric Sciences.
"We usually see cold water conditions for a few months once upwelling begins in late spring and early summer," Peterson said in an OSU press release. "Since April of 2007, though, we've been in a constant 'summer-state' ocean condition, which is something we've never seen in more than 20 years of sampling. And we're not sure why."
The conditions nurture masses of phytoplankton that are rich in fat and provide food for small fish such as anchovies and herring, which themselves become food for salmon and other predators. The word from researchers this year was that seabirds were getting plenty to eat and that it was a good year for ling cod and other rockfish.
-- Michael Milstein; michaelmilstein@news.oregonian.com