[env-trinity] NOAA: Ocean Indicator Report Shows Conditions In 2009 Worsen For Young Salmon In California Current
sari at sisqtel.net
Mon Jan 25 15:37:29 PST 2010
THE COLUMBIA BASIN BULLETIN:
Weekly Fish and Wildlife News
January 22, 2010
Issue No. 516
* Ocean Indicator Report Shows Conditions In 2009 Worsen For Young
Salmon In California Current
Living-feeding conditions for young salmon took a turn for the worst
in that 600-mile wide swath of water off the Oregon and Washington
coasts called the California current, according to NOAA Fisheries
"During the second half of 2009, the trend of cold ocean conditions
that began in 2007 and continued through 2008, changed noticeably,"
according to "Ocean Ecosystem Indicators 2009," according to the
annual update for a research project ongoing since 1996. "After June,
the ocean began to warm significantly, leading to detrimental changes
in the pelagic food web and likely high mortality of juvenile salmonids."
The shift doesn't bode well for returns of coho salmon to the
Columbia River basin this year. But researchers say the conditions in
2007-early 2008 should help swell spring chinook returns this year and next.
The project, "Ocean Ecosystem Indicators of Salmon Marine Survival in
the Northern California Current," is a product of NOAA Fisheries'
Northwest Fisheries Science Center Fish Ecology Division. The update
and related information can be found at:
The researchers sample a number of physical, biological and ecosystem
indicators to specifically define the term "ocean conditions." They
use the data collected to forecast the survival of salmon that begin
returning 1, 2 and 3 years later.
The forecasts are qualitative in nature, with each of the 18 ocean
indicators rated "good," "bad" or "neutral" relative to their
expected impact on salmon marine survival.
The biological indicators measured for the study are those
encountered by salmon during their first year at sea through
food-chain processes. The biological indicators, coupled with
physical oceanographic data, "offer new insight into the mechanisms
that lead to success or failure for salmon runs," according to the NWFSC.
"The ocean is not so much of a black box anymore," said NWFSC
researcher Bill Peterson.
The overall score for the indicator data in 2008 was the best ever
measured in the 12-year history of the study and those conditions
lingered, for the most part, into 2009. But many of the ocean
conditions changed drastically about mid-year in 2009.
"It doesn't look good," Peterson said of conditions at year's end
that left 2009 conditions as the seventh best recorded by the
researchers, despite the strong start.
"Poor ocean conditions during 2003-2006 began to improve during 2007
and greatly improved during 2008," the update says. The most negative
winter Pacific Decadal Oscillation since 2000 and most negative
summer PDO since 1955 were seen in 2008.
The PDO is a climate index based upon patterns of variation in sea
surface temperature of the North Pacific. A negative or cool phase
PDO is generally considered to benefit salmon. Likewise a cool El
Nino/Southern Oscillation pattern is believed to help boost salmon
survival. Both the PDO and ENSO turned from good to bad last year.
The PDO typically over the long-term past have persisted in cool or
warm phases for decades at a time. But in recent years time spans for
either phase have been much shorter, sometimes just a year or two.
"It's misbehaving. It hasn't settled into a nice regular pattern,"
Peterson said. "We need more (cool) years if we're going to build up
"Also in 2008, we observed the coldest winter sea surface
temperatures of the past 12 years (and probably since the 1970s) and
the earliest biological spring transition and highest northern
copepod biomass of the past 13 years," according to the update posted
on line this week by the NWFSC. "The latter included an anomalously
high biomass of the large, lipid-rich subarctic copepods" that
bolstered the food chain.
"During the first half of 2009, the PDO initially continued the same
trend observed in 2008, that is, a strongly negative signal through
winter and spring. However, the strong negative PDO began to weaken
in June and abruptly turned positive in August."
"Based on superior ocean conditions during spring-summer 2008, we
expect spring chinook runs in 2010 to rival the high returns of this
species seen in 2001 and 2002," the update says. The two highest
spring chinook returns on record were in 2001 and 2002.
"This was our forecast last year based on ocean indicators, and our
expectation is now supported by high returns of spring chinook jacks
in fall 2009," the update said. Jacks are spring chinook that return
after only one year in the ocean.
"We should still see a pretty good return next year," Peterson said.
"However, expectations for returns of coho in 2010 are considerably
lower due to warm sea-surface conditions throughout August 2009 and
low catches of coho salmon in our June and September surveys," the update says.
The low juvenile coho count during the trawl surveys may stem from a
dramatic cessation of upwelling in late summer that stopped the flow
of cool water and nutrients to the surface.
The annual transition to coastal upwelling began early, March 23, but
"winds were weak and inconsistent, especially after May. An early
start to the upwelling season is a necessary condition for good
survival; however, despite the early start of the 2009 upwelling
season, upwelling was weak, and had ended by early September," the
The researchers theorize that warm conditions may have led to the
demise of young coho, which reside in the upper few meters of the water column.
"It just stopped," Peterson said of the unusually curt end to coastal
upwelling season. "That's what hurt the catch" of juvenile coho in September.
The metrics monitored by NWFSC researchers include large-scale ocean
and atmospheric indicators such as the PDO and ENSO and local and
regional physical indicators such as sea surface temperature, coastal
upwelling of nutrients, the strength of the springtime transition to
upwelling and deep-water temperature and salinity.
Biological indicators include measures of the quality and quantity of
organisms that build the near-shore food chain and the actual
netting, and counting, of young fish. Juvenile salmon caught during
June and September trawl surveys off the coast serve as an index or
surrogate measure of ocean survival for spring chinook and coho salmon.
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