conditions for salmon headed to sea this year are very poor, according to
recent NOAA Fisheries research surveys, and have a high likelihood of
depressing salmon returns to the Columbia River in the next few years.
outlook is described in a recent research memorandum https://www.nwfsc.noaa.gov/research/divisions/fe/estuarine/oeip/index.cfm
NOAA Fisheries’ Northwest Fisheries Science Center, which has been studying the
ecology of young salmon entering the ocean for more than 20 years. The research
has helped reveal how conditions in the ocean affect salmon survival and,
ultimately, how many salmon complete their life cycle to return to their home
streams and spawn a new generation of fish.
Fisheries researchers regularly survey ocean conditions off the Pacific
Northwest Coast, focusing especially on factors known as “ocean indicators”
that can serve as barometers of salmon survival.
also assess the number and condition of juvenile salmon along the Oregon and
Washington coastlines, since the survival of the fish during their first months
at sea helps predict how many are likely to survive over the longer term.
Fisheries’ many years of ocean research have helped scientists develop online
charts of ocean indicators that display the forecast for salmon returns in
coming years. In the last few years the indicators have turned largely negative
for Columbia River salmon, in large part because of unusually warm ocean
temperatures, including the “warm blob,” a large swath of warm water that
encompassed much of the West Coast beginning in 2013.
is not just about salmon, however, it’s about an ocean ecosystem that is
changing in ways that affect salmon and everything else out there,” said David
Huff, manager of the NWFSC’s Estuarine and Ocean Ecology Program. “Remote
methods of detecting changes to the ecosystem did not highlight the poor ocean
conditions this year. For example, the warm blob has dissipated, so satellite
imagery shows near-normal sea surface temperatures. It was only by getting out
on the water and sampling directly that we were able to identify and describe
local biological indicators.”
catch of juvenile salmon this year was among the lowest in the last 20 years,
suggesting that the early survival of young fish was unusually low. Catches of
other species such as smelt, herring, and anchovy were also low, a sign that
predators such as seabirds near the mouth of the Columbia may have had to rely
more heavily on young salmon just entering the ocean.
in recent years have also turned up record numbers of warmer-water species such
as Pacific pompano and jack mackerel that previously had been scarce off the
Pacific Northwest coast. Increased abundance of these warm-water species can
have direct and indirect ecological impacts on salmon.
warm ocean waters typically carry plankton with less of the fatty nutrients
that young salmon need to thrive when they first go to sea, starving the food
web from the bottom up. This year researchers noted that chlorophyll, which is
a barometer of the plankton that helps sustain higher trophic levels, was at
its lowest levels in 20 years.
the same time, tiny marine crustaceans called copepods that signal favorable
conditions for salmon have remained at low levels since 2014, researchers said.
results indicate that salmon fisheries may face some lean times in the next few
years. Biologists will report on 2017 salmon returns later this year, and will
issue forecasts for 2018 in early March. Those forecasts will help shape
expectations for 2018 fishing seasons.
the news is not good, this new information helps us anticipate what’s coming,”
said NWFSC Director Kevin Werner. “We cannot change what the ocean is doing in
the short term but this scientific information can help us make good decisions
about how best to manage and protect salmon in light of these adverse
findings underscore the vast influence the ocean exerts over salmon survival
and the importance of providing salmon with healthy freshwater habitat so they
can weather poor ocean conditions and take advantage of favorable conditions
when they return. That is a central focus of NOAA Fisheries’ recovery plans for
threatened and endangered salmon and steelhead.
difficult as it is for salmon right now, tribes, watershed groups, and others
across the region have worked hard to improve freshwater salmon habitat,” said
Michael Tehan, Assistant Regional Administrator for the Interior Columbia Basin
Office of NOAA Fisheries’ West Coast Region. “That’s essential for sustaining
salmon through these tough times so they can rebound when ocean conditions
Returns and Ocean Conditions (NWFSC fact sheet) https://www.nwfsc.noaa.gov/publications/documents/salmon-returns-ocean-conditions-2017.pdf