New Research Reveals Flawed Approach to Salmon Recovery Programs – With Major Implications for Dams Debate
Northwest RiverPartners Welcomes New Peer-Reviewed Report, Emphasizing the Need for a Fresh Look at Policies
Nov 2, 2020—Newly published research has unveiled remarkable insight into the
survival rates of Chinook salmon populations along the North American West
Coast, highlighting a dramatic omission in the way such data has been
interpreted for over two decades.
The peer-reviewed research entitled, “A Synthesis of the Coast-wide Decline in
Survival of West Coast Chinook Salmon” has been published by the leading
science journal, Fish and Fisheries. The research was carried out by a team
from Kintama Research, led by the award-winning Dr. David Welch, who has
been involved in marine research on salmon for 40 years and recognized globally
for his work.
Importantly, this pivotal research comes at a time when many interest groups
continue to press for the removal of productive, cost-effective hydroelectric dams,
despite the region’s aggressive carbon reduction goals. Many believe that the
federally-operated dams are preventing the recovery of threatened and
endangered salmon populations – specifically in the Snake River, the largest
tributary of the Columbia in the Pacific Northwest.
However, Dr. Welch’s research questions that conclusion. The study reveals that
Chinook salmon survival has fallen by two-thirds, on average, for almost all
regions along the western coast of North America – in both dammed and
undammed areas – and not just in the Columbia River Basin.
The study is supported by deep technical and scientific analyses of the extensive
survival data collected by government agencies over many decades. The
research also reveals that survival is indistinguishable for Puget Sound and
Snake River spring Chinook populations, despite the absence of major dams in
the Puget Sound region.
The implication of the research is that the shared ecosystem of all Pacific
salmon, the Pacific Ocean, is likely the source of the coastal-wide decline in
Chinook salmon populations. Dams, while having some effect on salmon
survival, do not appear to be a key limiting factor for recovery.
Harvest Omitted
Dr. Welch’s scientific analysis also found a significant flaw in the models used to
produce adult survival estimates for the Columbia River Basin salmon. The two
predominant models used to formulate regional salmon policy both rely on PIT
tag data–small RFID tags implanted in some fish, which only track salmon when
they swim past in-river receivers.
Adult salmon caught in fisheries in the ocean or river are not counted by these
monitoring systems, meaning that harvest is ignored in the models. The
assumption by the modelers is that harvest is insignificant and stable from year
to year, so excluding it isn’t a problem.
In contrast, Dr. Welch’s research found that harvest of Columbia River Chinook
stocks can be large–as much as 75% of the total salmon run for some Columbia
River populations–and highly variable over time.
This finding means that the predominant models fail to recognize that the reason
for good or bad salmon returns may have been strongly influenced by how a
range of US federal, state, and Canadian agencies were regulating the adult
salmon catch.
As a result, the model outcomes are unintentionally providing erroneous
information.
This new research clearly shows a need to revise the models and, ultimately,
salmon policies themselves.
No Evidence for Delayed Mortality
Those who oppose hydroelectric dams with advanced fish passage systems
often refer to the theory of delayed mortality. This assumption is rooted in the
unproven idea that juvenile salmon are injured by successive dam powerhouses
and fish bypass systems, reducing their survival in the ocean.
However, Dr. Welch makes a convincing case that there is no real evidence for
delayed mortality in the data. He provides solid reasoning, using data from both
the Fish Passage Center and other independent datasets, that greater dam
passage does not usually cause lower survival rates.
This finding is critical, because policies based on the delayed mortality theory
have cost the region billions of dollars and increased our carbon footprint without
addressing the real issues leading to lower salmon survival–climate change and
warming oceans.
The governors of Oregon and Washington both recently pointed to the region’s
devastating and deadly wildfires as signs that climate change will continue to
have a very negative effect on Pacific Northwest communities. Dr. Welch’s study
shows that they should be similarly concerned about the oceanic impacts of
climate change and their effects on salmon survival.
This conclusion means that our carbon-free hydropower resources are more
important than ever.
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About Northwest RiverPartners
Northwest RiverPartners (NWRP) is a not-for-profit, member-driven organization.
We represent not-for-profit, community-owned utilities across Washington,
Oregon, Idaho, Montana, Wyoming, and Nevada. We also proudly represent
farmers, ports, and businesses across the region that support clean energy and
low-carbon transportation.
NWRP is focused on raising awareness about how the Northwest’s hydropower
system betters communities and the natural environment, and we encourage
science-based solutions that help hydropower and salmon coexist and
thrive. http://www.nwriverpartners.org