New Findings Cast
Doubt on CDFG Fish Die-Off Assessment
Recent findings incorporated into a declaration
submitted in an upcoming court case suggest that a
report released earlier this year by the
California Department of Fish and Game (CDFG)
contains “several major errors”. David Vogel, a
fisheries biologist with 28 years experience,
recently submitted information to an Oakland judge
that raises serious questions about the CDFG
report, which has been hailed by environmental
activists as proof that Klamath Project operations
were responsible for the death of 33,000 salmon in
the lower Klamath River last fall. The California
Resources Agency concluded within days of the fish
die-off that operation of the Klamath Project,
located 200 miles upstream of the die-off, was
somehow to blame. A report released by CDFG two
months later reaches the same conclusion.
According to Vogel, CDFG’s report contains several
CDFG inappropriately uses monthly average air
temperatures and monthly average water
temperatures to derive conclusions on potential
cause and effects on the fish die-off. The use of
monthly averages can mask important daily changes
in temperatures stressful to fish.
CDFG incorrectly plotted water temperature data
collected in the area of the fish die-off; CDFG
mistakenly plotted water temperature data in the
lower river skewed four days earlier than when the
data were actually collected. The significance of
this is that CDFG’s report misrepresented
important water temperature data collected just
prior to and during the period of the fish
CDFG fails to explain the relationship between
cooling water temperatures and the peak run of
salmon that occurred in late August in the lower
river. Yurok Tribe biologists noted a pronounced,
and uncharacteristic, cooling trend in the lower
river occurred in late August. According to the
CDFG fish die-off report, an early,
uncharacteristic peak run of salmon occurred
concurrently in the lower river. Those data
suggest that large numbers of salmon likely
entered the lower river earlier than usual in
response to the sudden cooling trend. However, a
pronounced warming trend followed which exposed
the undoubtedly crowded fish that had already
entered the river to stressful conditions. By the
second week in September 2002, a precipitous
decline in water temperatures occurred that likely
prompted even more fish to enter the lower river.
CDFG’s speculation concerning a physical fish
passage barrier in the lower Klamath River is not
supported because: 1) fish passage occurred in
other years with similar or less flow; and 2) data
in the CDFG report demonstrates fish passage
occurred during the flow conditions present prior
to the fish die-off.
Of note, CDFG asserts that toxic substances could
not have caused the fish die-off, even though it
admits that water samples were not taken until 7
days after the onset of the fish die-off.
Therefore, that potential source of mortality is
still in question. To date, Vogel is unaware of
any evidence ruling out the possibility that toxic
substances may have caused the fish die-off.
Myth vs. Fact:
2002 Fish Die-Off
KWUA questions arguments made by environmental
advocates and tribal biologists because they do
not articulate how increased releases from Iron
Gate Dam (IGD) could have prevented the 2002
Klamath River fish die-off more than 170 river
miles downstream of the dam. If the primary cause
of the fish die-off was warm water, it was
physically impossible for IGD to cool the river
down to tolerable levels for salmon.
MYTH: Increased IGD releases in the upper river
could have ameliorated water temperatures in the
FACT: Maximum water temperatures in the upper
Klamath River were much higher than the lower
river just prior to the fish die-off and very
similar during the time of the fish die-off.
MYTH: Increasing upper Klamath reservoir releases
during late summer or early fall during naturally
dry hydrologic conditions, such as occurred in
September 2002, would benefit salmon.
FACT: Due to a variety of meteorological,
physical, and biological reasons, artificially
increasing flows at that time would probably be
harmful. This is because IGD discharges are too
warm for salmon during much of September.
MYTH: Additional Klamath Project flows released
from Iron Gate Dam in early September 2002 would
have prevented the fish die-off.
FACT: There is no evidence that releasing more
water from IGD during early or mid-September could
have prevented a fish die-off more than 170 river
miles downstream because upper main stem
temperatures were within the range known to cause
mortality or reproductive failure in salmon. The
gradual declining temperatures in the Klamath
River downstream of IGD during the fall are
primarily attributable to normal seasonal declines
in ambient air temperatures, not river flow.
MYTH: 2002 was unique because there was a large
salmon run and low Iron Gate Dam flows, which
explains the fish die-off in September 2002.
FACT: Contrary to this claim, 1988 had a much
larger salmon run than 2002 and the lower Klamath
River flows were similar to that observed in 2002.
According to the CDFG fish die-off report, in 1988
the lower Klamath River flow during September was
2,130 cfs, the salmon run was 215,322 fish and
there was no consequent fish die-off; in 2002, the
lower Klamath River flow during September was
2,129 cfs and the salmon run was 132,600 fish.
These facts provide empirical evidence that this
assumption is invalid.
Former Executive Director Klamath Water Users