The physical and
biological ocean conditions that greeted young salmon flooding
from the Columbia River this past spring have never been
better, at least since monitoring began in 1996.
very well for future returns of coho, spring chinook and
"… all signs to date indicate very high returns of coho,
almost certainly rivaling the 4 percent numbers seen for fish
that entered the sea in 2000 and 2002," according to an adult
return forecast updated this week by NOAA Fisheries Service
researchers. Coho leave the freshwater each spring as year-old
smolts and return the following fall.
State biologists estimate that 1.1 million coho returned to
the mouth of the river in 2001, the highest return since 1986.
The total in 2003 was 677,000, according to the 2008 Joint
Staff Report of the Oregon and Washington departments of fish
"Spring Chinook runs in 2010 and 2011 are also expected to
rival the high returns seen in 2001 and 2002," according to
the NOAA adult return forecast. The spring chinook also leave
the river as yearlings but spend more time at sea. The upriver
spring chinook return to the river mouth in 2001 was 437,900,
which is the most on a record dating back to 1938. The 2002
return was 331,000.
"I'm really excited about this," Newport, Ore., based NOAA
oceanographer Bill Peterson said of the list of oceanic
variables monitored as part of the ongoing study. For the
first time during the study's 11-year history all were judged
favorable for the young fish. A cold ocean off the coasts of
Oregon and Washington is good for salmon, as well as other
marine fish and bird species.
The winter of 1999-2000 was "the first cold year that we'd
had in a long, long time," Peterson said. The coho seemed to
respond with a near doubling of their return rate.
Pacific Decadal Oscillation values shifted from neutral
through most of 2007 to negative last September, entering a
cold phase that turns the California Current cold. The PDO is
a measure of climate variability that shifts on at least an
inter-decadal time scale and usually on about 20- to 30-year
time scales. The current is a 30-40 mile swath of ocean along
the West Coast.
Those strongly negative values remained entrenched through
"When the behavior of the PDO over the past 11 years is
compared, we find that the most negative value of the PDO for
the winter months occurred in winter 1999-2000," according to
this week's ocean indicators update. "The winter of 2007-2008
is the second most negative. This is an important leading
indicator because Logerwell et al. (2003) showed that one
pre-requisite for good coho salmon survival is that a cold
winter should precede the spring months when the fish enter
the sea. We assume that the same is true for yearling Chinook
The good PDO news has continued through August.
"Should the PDO remain strongly negative through September,
the year 2008 will become the most negative PDO summer since
the 1950s," the update says.
Each of the monitored "indicators" -- such as food
availability and water temperature -- are ranked by the
researchers in comparison to the same indicator down through
the years. Peterson leads cruises every two weeks to collect
on coastal upwelling of nutrients, water temperature and
salinity characteristics, and plankton species compositions,
among other elements.
Seven of the 12 indicators for which data is available so
far this year rank No. 1 among the 11 years of data in terms
of being favorable for fish. The mean rank for 2008 for all 12
variables is 1.8 with the lowest ranked indicator being the
fourth most favorable recorded in study history.
"As of the end of August 2008, all of our ocean indicators
remain highly favorable for high rates of growth and survival
of salmon that entered the ocean this spring and summer," the
update says. "In fact, by the end of the upwelling season (in
September) when all of our indicators are averaged, 2008 will
almost certainly be the most outstanding year in our 11 year
The El Niño/Southern Oscillation, another climatic
influence that shifts more quickly over time, also favors fish
growing off the Northwest coast. Averaged over the
January-June period, ENSO values are the most negative in the
11-year history of the NOAA study and the lowest since 1988.
Likewise, sea surface temperatures are now the coolest in
The annual "spring transition" began in early March this
year, with wind driven currents shifting from a northward to a
southward flow. The change brought zooplankton south from the
Gulf of Alaska to enrich waters for newly arrived salmon.
"This is a positive sign for fisheries because it means
that the food chain was populated by northern species very
early in the year," the update says.
A cold PDO and sea surface attracts favored prey. Bigger,
fatter copepod species from the north, as opposed to less
sumptuous subtropic copepods, give a big boost to salmon
"Of particular interest in 2008 (and 2007) has been the
presence of large numbers of the very large and lipid rich
Neocalanus species," the research update says of the largest
of the copeod species. "They frequently occur off the Oregon
coast during winter and spring months, and their presence
indicates that sub-arctic waters off Oregon; however during
both 2007 and 2008 the species N. plumchrus has been roughly 5
times more abundant than during the previous 'cold phase' of
"Moreover, high numbers were seen far offshore to at least
125 miles from shore suggesting that the more oceanic species
of fishes will benefit (such as sablefish)."
The NOAA researchers qualify their adult return forecasts
as being qualitative, meaning that the understanding of each
indicator's influence on the young fish is not yet developed
enough to enumerate future adult returns. But that
understanding is growing with each passing year, said John
Ferguson, head of the Fish Ecology Division at NOAA's
Northwest Fisheries Science Center in Seattle. Peterson and
other FED scientists are carrying out the "Ocean Ecosystem
Indicators of Salmon Marine Survival in the Northern
California Current" research.
Trawl surveys conducted in June off the coasts of Oregon
and Washington netted the highest number of juvenile spring
chinook salmon in those 11 years – 2 ½ time more than the next
highest total, Peterson said.
"The correlation would say that if you see them there and
they're in good condition, there's going to be stronger
recruitment to the adult stage," Ferguson said.
"That's a very important time for them," Ferguson said of
those first few months in the ocean. "Physiologically, they
are geared to grow."
If a bountiful ocean awaits they will indeed grow quickly,
increasing their ability to escape predators and, in general,
"We were buried in fish," Peterson said of the June
trawling, which nets mostly spring chinook but also some coho
and sockeye. Last year's June catch of sockeye was a record
for the study – a total of 58.
"This year it was in the hundreds," Peterson said.
The researchers are getting ready for the annual September
trawl surveys, ranging out from as far south as Newport, Ore.,
and as far north as LaPush, Wash. Those forays net mostly coho.