The inappropriate use of 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 die-off.

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.

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, KWUA is unaware of any evidence ruling out the possibility that toxic substances may have caused the fish die-off.