Approximately 800,000 juvenile salmon died from an unknown disease shortly after being released into a river in California, USA, to help improve the salmon population.
A large number of Chinook salmon died last week after officials from the California Department of Fish and Wildlife (CDFW) released them into the Klamath River, a 414 km river flowing through southern Oregon and northern California.
Approximately 800,000 juvenile salmon were released into the Klamath River in California last week – (Photo: CBS NEWS).
According to CBS News on March 3, CDFW reported that about 830,000 Chinook salmon – newly hatched at the Fall Creek hatchery – are believed to have died due to “gas bubble disease” in the Klamath River.
Meanwhile, the Daily Mail (UK) headlined: “Mysterious disease kills 800,000 salmon just released into a California river to help improve salmon populations.”
The state of California has committed to supporting and restoring both Chinook and Coho salmon in the Klamath River. Earlier last week, CDFW released these salmon into Fall Creek, a tributary of the Klamath River upstream of the Iron Gate Dam.
Monitoring data downstream indicated that a significant number of juvenile salmon had died. According to CDFW, many signs suggested that the deaths were caused by gas bubble disease, which can occur when they move through the Iron Gate Dam’s tunnel.
Gas bubble disease arises from physical or environmental trauma, often associated with severe pressure changes.
According to veterinaryvisioncenter.com, this disease – which occurs in both farmed and wild fish – causes gas bubbles to form in small blood vessels, particularly affecting the fins, gills, eyes, and sometimes vital organs.
Chinook salmon – (Photo: CBS NEWS).
CDFW stated that there were no signs indicating that the deaths were related to the water quality of the Klamath River, such as turbidity and dissolved oxygen levels, which were both at appropriate levels on February 26 and in the days leading up to the fish release.
CDFW pointed out that the issues related to the Iron Gate Dam’s tunnel are only temporary, but this continues to be “a sad reminder of how dams on the Klamath River have harmed salmon over many generations.”
CDFW indicated that in the future, they plan to release salmon below the Iron Gate Dam until the dam is removed.
