The near edge of that "black box" called the
Pacific Ocean has been pried open by NOAA
Fisheries scientists who say they can gauge how
well juvenile salmon and steelhead survive
during that crucial time when they move from
Columbia River freshwater to saltwater.
Fish managers, Columbia River basin policymakers
and others point to the dynamic Pacific Ocean as
a cause of wide variations in salmon returns
from year to year. But little is known about
what causes those changes other than effects
from shifting water temperature and availability
of food resources for the salmon.
NOAA scientists have, however, since 1998 been
trying to learn how each of numerous changing
physical and biological indicators in the
Northern California Current ecosystem affect
juvenile salmon survival. They expect the work
will soon provide an additional tool for
predicting, based on those survival estimates,
the size of the returns the following year or
The work attempts a "deconstruction of what
people call the black box in the ocean,"
according to John Ferguson, director of the Fish
Ecology Division at NOAA's Northwest Fisheries
Science Center in Seattle. The ocean is hard to
study, and impossible for man to manipulate. It
remains largely a deep and mysterious place
where conditions can change drastically, from
day to day, and from decade to decade.
"The variability in freshwater is slight
compared to the variability in saltwater,"
Ferguson said of the conditions salmon face
throughout their life cycle.
The California Current is the flow that surges
east from mid-ocean and hugs the southern
British Columbia, Washington and Oregon coasts
as it continues southward. Its temperature can
change up and down. A pattern called the Pacific
Decadal Oscillation shifts from positive to
negative in terms of how it affects salmon
Changes occur too in ocean productivity -- the
amount of animal and plant life it provides.
That affects salmon maturation and survival. And
it affects the survival of fish that prey on
NOAA's Northwest Science Center has been
monitoring the coastal ocean environment off
Washington and Oregon, including an assessment
of the Columbia River plume, its interaction
with the California Current and how it affects
the abundance, distribution and growth of
juvenile salmon as a means to assess their
survival as they enter the marine landscape.
Physical and biological features have been
assessed over time frames to evaluate how each
might affect survival. The resulting indicators
can be tabulated to estimate how the young fish
might fare in any given year.
Marine survival is very important. NOAA
estimates that an increase in survival of from 1
to 2 percent would double the size of the adult
return to freshwater.
Current salmon return forecasts are based in
large part on the number of "jacks" and other
age-classes that return the previous year. Jacks
are salmon that return prematurely, before they
are old enough to spawn. Fisheries experts
estimate what share of a brood year's output
that the jacks represent. Their broodmates
return in subsequent years to spawn.
NOAA's indicator assessments will in June and
September be able to predict how many jacks
might return the next year based on the
conditions the smolts faced in the plume and
"By June we can have a pretty good idea of the
physical condition of the ocean" and how salmon
might respond to those conditions, Ferguson
said. By September, biological conditions such
as food availability and predator population
status can be added in to the equation.
As an example, 2007 chinook salmon returns, and
this year's coho run, are expected to be down
from those of the recent past. Jack counts so
far this year have been lower than those of
recent years that foretold higher than average
"Indicators predominately turn bad in 2005" and
have stayed that way, Ferguson told the
Northwest Power and Conservation Council during
a Wednesday progress report on NOAA's findings.
The PDO, ocean upwelling of nutrients and
predator abundance and other indicators are less
unfavorable for juvenile salmon growth and
survival during the period following ocean entry
-- the early summer and fall.
The Columbia River plume -- a
freshwater/saltwater solution where the young
fish can steady themselves before venturing off
into the ocean -- can vary from day to day,
growing or shrinking, drifting north or south,
changing shape. The plume is whipped by the
wind, and changed by the quantity of outflow
from the Columbia. The latter can be manipulated
to some degree by Columbia hydro operations.
NOAA had linked the size of the plume to the
size of the steelhead return, generally larger
the plume upon the juveniles entry, the larger
the return of that brood class.
"It's very important for yearling fish," said Ed
Casillas, manager of the center's Estuarine and
Ocean Ecology Program.
NOAA's next step is to put the information in a
format that will be readily available to
management entities. The agency plans to
evaluate the indicators annually and communicate
the status of the Northern Californian Current
Ecosystem annually through a technical report,
as well as post the information in "real time"
on the agency's web site for fishery managers to
The forecasts should help managers make
decisions -- such as setting harvest targets,
adjusting hatchery production during periods of
poor ocean productivity and placing more or less
emphasis on hydropower prescriptions and
freshwater restoration activities depending on
The assessments should help in "getting the
right number of fish to the ocean at the right
time," Ferguson said.
"Our scientists are about to complete important
research on the huge influence that changing
ocean conditions have on salmon from the time
they migrate as juveniles through the estuary
into the ocean to when they return as adults,"
NOAA's regional administrator, Bob Lohn said of
"This ongoing research will help future salmon
management decisions," he added.
In a press release issued Thursday, Lohn noted
that the 2006 upriver spring chinook return was
higher than the 10-year average.
"The long-term average continues to rise," Lohn
said. "I'm convinced that efforts we've made to
improve fish passage through the dams,
significant investments to enhance fish habitat,
and our current hatchery and harvest management
reforms will help salmon recover for the long
Those improved in-river conditions do not always
translate into larger runs because the ocean's
"The poor ocean conditions we observed in 2004
and 2005 lead us to expect lower rates of return
for spring Chinook in 2007," Lohn said. "The
counts of jacks – the early-returning fish from
the juveniles that migrated to the ocean in 2004
and 2005 – are about two-thirds of last year's