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<br><br>
<font size=4><b>Salmon Survival: It’s All About The Early Days In The
Ocean And 2010 Tough To Call <br>
</b></font>Posted on Friday, January 07, 2011 (PST) <br><br>
<font face="Times New Roman, Times">Ocean conditions off the coast of
Oregon and Washington changed from nightmarish to dreamy for juvenile
salmon this past late spring-early summer and in the process confounded
experts’ efforts to predict how those young fish may have fared.<br><br>
<br><br>
“The fact that ocean conditions were poor early in the season but great
later in summer makes it impossible to provide any reliable forecast this
year: our best ‘guess’ is that we can expect near ‘average’ returns in
2011 (for coho) and 2012 (for chinook),” according to the Northwest
Fisheries Science Center’s annual qualitative prediction of future
returns. “We do not think that the El Niño had a devastating effect on
salmon because the warm ocean conditions at the time of ocean entry (in
April/May) were about ‘average.’”<br><br>
<br><br>
NOAA Fisheries’ NWFSC has over the past 13 years developed a suite of
ocean ecosystem “indicators” that are monitored and the data then used to
estimate what kind of an impact they might have had on juvenile salmon
during the earliest stage of their ocean sojourn. Basically, the better
the survival early on, the more fish are expected to survive to adulthood
to return to the Columbia River basin to spawn.<br><br>
<br><br>
Each of the 18 or so indicators is rated for the year as good, neutral or
bad. Then they are compared individually to past measurements and, as was
the case this year, given a score of from 1 (the best combined score over
the course of the study) to 13 (the worst).<br><br>
<br><br>
The run-size forecasts are based on the average score for the indicators
overall. <br><br>
<br><br>
The mean of those scores for 2010 ranked the year eighth out of 13, which
would indicate slightly below average overall conditions for coho and
spring chinook salmon that ventured to sea last spring. The forecasts are
for the first year that species’ begin to return as fully matured adults,
in the coho’s case after one year in the Pacific and the spring chinook
after two years.<br><br>
<br><br>
“There’s some hints that it was not that terrible” for young fish that
typically would have entered the ocean before conditions turned from bad
to good, said Bill Peterson, NOAA Fisheries oceanographer and senior
scientist. The number of coho jacks that returned, as counted at
Bonneville Dam, after just a few months in the ocean was in the average
range, he said. The strength of a jack return can mirror the strength of
broodmate returns in succeeding years.<br><br>
<br><br>
In the California current that hugs the coast, and elsewhere, cold is
good for salmon.<br><br>
<br><br>
“Because of the 2009-10 El Niño event, the ocean began to warm in autumn
2009 and remained warm through April 2010, after which a cooling trend
resumed in May 2010,” the forecast says. The El Nino/Southern Oscillation
is the measure of sea surface temperatures in the equatorial Pacific that
can affect climate worldwide.<br><br>
<br><br>
“Thus, 2010 began as a ‘warm year,’ began to cool in May but by July, the
ocean was the coldest observed in recent years. Thus we had very mixed
signals in 2010 making it difficult to offer any reliable outlooks in
returns of coho salmon in 2010 and chinook salmon in 2012,” the forecast
says. <br><br>
<br><br>
“During the tail end of the El Niño, in May and June, we had some of the
worst ocean conditions we’ve seen in the 13 years we’ve been sampling,”
Peterson said. “Then in July, the conditions were as good as they’ve ever
been. So it’s a question of timing” and what the fish did once they
entered the ocean.<br><br>
<br><br>
Coho tend to hang out not too far off the coast and not too deep. The
spring chinook don’t seem to dawdle too long before charging north up the
continental shelf to parts unknown.<br><br>
<br><br>
At the time of the young fishes entry, “the ocean really was kind
two-layered” with warm surface water and cool water deeper that was
relatively plentiful in terms of nutrients on which juvenile salmon
feed.<br><br>
<br><br>
Survival may have depended on “if they had enough sense to go deeper,”
Peterson said. Coho and steelhead have a more shallow orientation than
chinook.<br><br>
<br><br>
“Vertical structure is really something we’ve really not thought about,”
Peterson said.<br><br>
<br><br>
For the past 13 years, Peterson and his colleagues have conducting trawl
surveys funded by the Bonneville Power Administration in June and
September from Cape Perpetua to La Push, Wash., counting the abundance of
juvenile salmon along the near-shore waters of the West Coast. The
survival rate of juvenile salmon is the key indicator for future salmon
runs, says Peterson.<br><br>
<br><br>
When salmon first enter the ocean, they must have enough food to not only
survive, but to grow rapidly enough to avoid predation. The smaller they
are, the more vulnerable they are to potential predators lurking
offshore. And when ocean productivity is high, populations of other fish
like herring, anchovies and sardines grow and provide alternatives for
the predators.<br><br>
<br><br>
Peterson said the juvenile chinook counted this summer was the fifth
highest they’ve had in their 13 years, raising hope for future chinook
runs. But the season’s mixed bag continued<br><br>
<br><br>
“We caught almost no juvenile coho salmon in September and that worries
me,” Peterson said.<br><br>
<br><br>
“We’ll find out soon enough,” he said. “Coho return as adults after 18
months; spring chinook come back after two years and fall chinook, three
years or longer. If these fish can make it to adulthood, they should be
fine. There’s not much that out there that feeds on them other than sea
lions and orcas.<br><br>
<br><br>
“It’s all about how they fare as youngsters,” he added, “and the jury is
definitely still out this year.”<br><br>
<br><br>
If the cool La Nina and negative Pacific Decadal Oscillation keep their
grip, conditions should be much improved by the time this year’s class
ventures out.<br><br>
<br><br>
SST anomalies were consistently colder than normal by several degrees
during the summer of 2010 and the deep water temperatures on the
continental shelf in July-August were the coldest of the 13-year record.
<br><br>
<br><br>
And the biomass of the lipid-rich “northern” copepod species was the
third highest on record during the summer of 2010. The northern copepods
are a key link in the food chain.<br><br>
<br><br>
The negative signals dominated early in the spring-summer season. The PDO
was positive (generally considered bad for salmon) and SSTs were warm
during the winter of 2009-2010 indicating poor ocean conditions during
the winter. <br><br>
<br><br>
The PDO is a climate index based upon patterns of variation in sea
surface temperature of the North Pacific from 1900 to the present. While
derived from sea surface temperature data, the PDO index is well
correlated with many records of North Pacific and Pacific Northwest
climate and ecology, including sea level pressure, winter land-surface
temperature and precipitation, and stream flow,” according to information
posted on NWFSC’s “Ocean Ecosystem Indicators of Salmon Marine Survival
in the Northern California Current” web site. That site is located
at:<br><br>
<a href="http://www.nwfsc.noaa.gov/research/divisions/fed/oeip/a-ecinhome.cfm" eudora="autourl">
http://www.nwfsc.noaa.gov/research/divisions/fed/oeip/a-ecinhome.cfm<br>
<br>
</a> <br><br>
The index is also correlated with salmon landings from Alaska,
Washington, Oregon and California.<br><br>
<br><br>
“Although the winter storms ended in late March and the upwelling season
was initiated on 5 April, strong upwelling was not initiated until two
months later, on 9 June,” according to the forecast. The length and
strength of the upwelling is indicative of the availability of fish food
delivered to the surface. <br><br>
<br><br>
“Within that two months period several southwest storms moved through the
region. This is generally a negative sign for salmon that enter the ocean
in April-May,” the forecast says. <br><br>
<br><br>
“Copepod species richness was very high during winter-spring-summer of
2010, ranking 11 of 13 from May-September. We regard this as a negative
sign because it indicates that the sub-tropical species that were brought
to Oregon with the El Niño persisted for several months after the end of
the El Niño event; species richness did not return to normal until autumn
2010.” <br><br>
<br>
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