Fish die-off a common occurrence on Klamath
Baun said that officials learned of the die–off during the week of July 7 when tagged juvenile Chinook salmon failed to show up near the Happy Camp area, with a subsequent search revealing many dead juvenile salmonids, as well as dead suckers, sculpins and a catfish at several thermal refugia areas.
Baun said that a definite cause hasn’t been determined for the deaths. He explained that the report of the dead juveniles was filed over the weekend after July 7, and when officials from California Fish and Game, who have regulatory jurisdiction over species management, went to the sites, they didn’t observe any dead fish, presuming that the bodies had been preyed upon since being discovered.
“The carcasses did not persist in the river, so additional data could not be collected from those carcasses,” Baun said, adding that mortality events of this kind are relatively common on the Klamath River during the hotter summer months when the water quality diminishes.
In a river like the Klamath, Baun explained, during the summer months, stressors such as disease and higher water temperatures pose a greater danger to juvenile salmonids.
Baun stated that these die–offs are usually something of a “mystery” and it can often be tough to pin–point which stressors cause the die–offs.
“Resource agencies simply do not have budgets to send crews out to conduct mortality surveys throughout the summer months and comprehensively monitor a river of this size,” Baun said, adding that inter–agency work can sometimes lead to delays as well.
While the event did have casualties, and a follow–up to the inital observation was conducted, Baun said, “There is no way of knowing the extent of this particular mortality event from July. Data from this event, as well as events from previous years, are limited in terms of total numbers and/or proportion of mortalities in relation to the overall population.”
Some citizens have voiced concerns about the die–off, but Baun said, “There is no evidence that this is something greater than what was initially observed.”