Fall-Run Chinook Salmon Fry Succumb to Gas Bubble Disease in California’s Klamath River
By angelamontana

Posted: March 7, 2024

In news to our west….

In a recent press release, the California Department of Fish and Wildlife reported that fall-run Chinook salmon fry released for the first time from Fall Creek Fish Hatchery in Siskiyou County faced significant mortality due to gas bubble disease in the Klamath River. Approximately 830,000 fry were released into Fall Creek, a tributary of the Klamath River, but downstream monitoring indicated a high mortality rate likely caused by gas bubble disease. This issue is linked to the outdated Iron Gate Dam tunnel, scheduled for removal later this year, and not to other water quality conditions. CDFW will adjust future salmon releases accordingly and continues to hold around 3.27 million healthy Chinook salmon at the hatchery.

Gas bubble disease, also known as gas bubble trauma, is a condition that affects aquatic organisms, particularly fish, caused by the formation of gas bubbles in their tissues or bloodstream. This occurs when dissolved gases, such as nitrogen and oxygen, come out of solution and form bubbles due to changes in pressure. Gas bubble disease can result from various factors, including rapid changes in water pressure, such as those caused by passing through dams or other underwater structures, or changes in water quality. The presence of gas bubbles in the fish’s tissues can impair their normal physiological functions, leading to symptoms ranging from tissue damage to death.

Gas bubble disease can occur in bodies of water across various regions, including Montana. However, its prevalence may vary depending on factors such as water quality, environmental conditions, and the presence of dams or other infrastructure that can contribute to pressure changes in the water. Wildlife management agencies in Montana, like the Montana Department of Fish, Wildlife and Parks, may monitor for gas bubble disease in fish populations as part of their conservation efforts.

Do you think the removal of the Iron Gate Dam Tunnel will eliminate the gas bubble disease issue in the Klamath River, or do you think there might be more to it?

(photo via California Department of Fish and Wildlife press release)
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