Not withstanding a few
"mixed signals," environmental and biological indicators
charted by the NOAA Fisheries Service's Northwest Fisheries
Science Center portray an ongoing transition to conditions off
the Oregon and Washington coasts that bode well for salmon
survival and growth.
"Ecosystem indicators measured in 2006
point to improving ocean conditions, suggesting higher adult
returns of coho salmon in 2007 and spring Chinook salmon in
2008," according to "Indicators Update: Spring 2007." The
NWFSC product was posted online last week: http://www.nwfsc.noaa.gov/research/divisions/fed/oeip/a-ecinhome.cfm
Those mixed signals, however, and the project's focus on
just a portion of the salmon life cycle, temper the forecast.
"Taken together, our indicators suggest that adult returns
of coho in 2007 and spring Chinook in 2008 will likely be near
to, but slightly below, returns averaged over the past
decade," the report says. The project, "Ocean Ecosystem
Indicators of Salmon Marine Survival in the Northern
California Current," plans to update the forecasts each year
after data is refreshed each June and September.
The indicators note shifting water temperatures and
conditions and the potential availability of food resources
for the salmon. June data collection tells the physical
condition of the ocean and September scientific sorties
offshore add to the picture with biological conditions such as
food availability and predator population status added to the
The goal of the forecasting project unveiled last year is
to provide a snapshot of what the yearling salmon experienced
when they left freshwater and entered the Pacific Ocean. Its
forecasts are qualitative rather than quantitative, rating
future returns as good, intermediate or poor, rather than
making numerical predictions.
"In that context we were right on," Ed Casillas, the
NWFSC's Estuarine and Ocean Ecology Program leader, said of
initial forecasts produced last year that predicted below
average 2006 coho and 2007 spring chinook returns.
"We don't want to get into that numbers game," Casillas
said, because of the "other forces that affect that return."
The young fish eventually disperse from the study area,
growing to maturity in different parts of the ocean and
experiencing varying conditions.
The data used has been retrieved by NWFSC since 1996 off
the California, Washington and Oregon coasts. The California
Current is a "broad, slow, meandering current" that flows
south from the northern tip of Vancouver Island to Punta
Eugenia near the middle of Baja, California, and extends
laterally from the shore to several hundred miles from land.
"It doesn't capture anything beyond that first summer,"
Casillas says of the study/forecast. The data tool is designed
to complement other forecasting indicators, such as jack
returns, smolt-to-adult return rates (Scheuerell and Williams
2005), and the Logerwell production index.
None of the existing forecast tools solves all of the
deep-sea survival mysteries. As an example, the researchers
run a trawling operation off the Oregon and Washington coasts
in June and September in an attempt to assess the relative
abundance of chinook and coho that had survived to that point.
The June 2005 trawl netted the fewest juveniles since that
operation began in 1998. It was followed in 2006 by the lowest
upriver spring chinook jack return to the Columbia since 1998.
The 2007 upriver spring chinook return -- featuring
4-year-olds from that 2005 outmigration -- was the lowest
In June 2006 the trawlers netted considerably more juvenile
chinook, though still less than the average over the course of
the study. That's one signal that the 2007 jack and 2008 adult
returns could increase.
The actual upriver spring chinook "jack" return this year
from that 2006 outmigration skyrocketed with Bonneville Dam
counts the third-highest ever recorded on the University of
Washington's DART web site -- after 2000 and 2003.
"They're higher than we would have predicted," Casillas
said. The jack counts are strong indicators but do not
foretell the magnitude of the next year's return. The 2000
record jack count, 21,000, was followed by a record adult
return of more than 400,000 upriver spring chinook. The 2003
jack count was more than 14,000, and was followed by an adult
return of 190,000. That was a relatively high return but
undershot numerical preseason forecasts, which were based in
large part on the previous year's jack counts, that year by
nearly 50 percent.
This year's jack count was similar to that of 2003.
The trawling picks up coastal coho stocks, as well as from
the Columbia River, Washington coast, the Puget Sound and
Vancouver Island with the Columbia stocks representing about
half of the total, Casillas said. Likewise, upriver Columbia
River spring chinook stocks represent about half of the catch
that includes fall chinook from the basin that are released as
The NWFSC researchers use three sets of indicators in an
attempt to better understand the interactions among juvenile
salmon and their environment. The first is based on
large-scale oceanic and atmospheric conditions in the North
Pacific Ocean, and consists of the Pacific Decadal Oscillation
and the Multivariate El Niño Southern Oscillation Index.
The second set is based on local observations of physical
and biological ocean conditions off Newport, Ore. The third
set is based on biological sampling of plankton, juvenile
salmonids, forage fish, and Pacific hake off the coast as part
of a Bonneville Power Administration-funded research program.
Each of the variables within those sets is ranked each
spring and fall -- good, intermediate or poor.
The data collected last month was almost universally "good"
with the PDO getting the only intermediate rating among the 11
variables assessed. That means the spring chinook that would
begin returning as adults in 2009 likely met favorable
conditions upon entering the ocean this year.
"Cold" oceans conditions -- cooler than average -- are
generally considered good for chinook and coho while warm
conditions are not.
"The year 2006 marked what now appears to be the beginning
of a transition from the poor ocean conditions observed in
2004-2005 to very good conditions in 2007," the report says of
the PDO, climate index based upon patterns of variation in sea
surface temperature of the North Pacific.
A warm-phase PDO prevailed during most months from August
2002 through July 2006, but since July 2006, PDO values have
either been negative or near zero. A PDO of zero indicates a
neutral state, which suggests "average" ocean conditions. A
"warm ocean" trend in more localized Sea Surface Temperatures
began in November 2002, but abated from late 2005 through
"From June 2006 to May 2007, cooler-than-normal SSTs have
been observed in the coastal upwelling zone. Therefore,
implications for salmon survival are 'mixed' in terms of SST
-- warm SSTs in early 2006, when salmon first went to sea,
were a negative indicator, but cooler SSTs, which have
continued into 2007, are a positive sign," according to the
"Local ocean conditions reflect theses changes, with
coastal upwelling and the physical spring transition date
creating conditions that should benefit salmon survival.
That transition included a bit of a hiccup last year,
causing some uncertainty about the fate of the young coho and
chinook that went to ocean. The annual upwelling of nutrients
began in early May, but atmospheric conditions changed
drastically after just two weeks. Strong southwesterly storms
moved up the coast and "may have erased or 'reset' any
signature of upwelling."
As a result the so-called biological transition -- the
appearance of the kind of food chain that coho and chinook
salmon seem to prefer -- did not occur until May 30.
The latest report also does not capture poor ocean
conditions that prevailed from April through mid-June, 2006.
"Thus, salmon encountered poor ocean conditions during
their first weeks in the ocean, which likely had a negative
impact on survival," the report says. The researchers plan to
subdivide the data for future reports, characterizing ocean
conditions in late winter/early spring and from June or July
through September, when salmon that survive ocean entry
experience rapid growth.