[env-trinity] NOAA: Ocean Indicator Report Shows Conditions In 2009 Worsen For Young Salmon In California Current

Sari Sommarstrom sari at sisqtel.net
Mon Jan 25 15:37:29 PST 2010

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 
Service scientists.

"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 
salmon populations."

"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 
update says.

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.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www2.dcn.org/pipermail/env-trinity/attachments/20100125/31eb4c17/attachment.html

More information about the env-trinity mailing list