A Strange Disease Devastates Salmon Fry In PNW River.

In a tragic incident, approximately 830,000 salmon fry released into Northern California's Klamath River met a devastating fate, succumbing to gas bubble disease as they navigated the Iron Gate Dam tunnel.

High Mortality Linked to Pressure Changes

The California Fish and Wildlife Department revealed this unfortunate event, attributing the high mortality rate to the severe pressure change experienced during the passage.

Silver Lining: Removal of Tunnel and Dam

The silver lining is the impending removal of the tunnel and dam later this year. These Chinook salmon fry, the first release from the Fall Creek Fish Hatchery, faced unforeseen challenges on their journey.

Historical Impact of Klamath River Dams on Salmon

The incident serves as a poignant reminder of the historical impact of Klamath River dams on salmon runs, echoing the region's once vibrant status as the third-largest salmon-producing river on the West Coast.

Gas Bubble Disease: Culprit Identified

Monitoring data downstream suggests gas bubble disease as the culprit, a condition linked to environmental or physical trauma during pressure changes. While there's no indication of other water quality issues, the visual evidence points to the temporary yet impactful harm caused by the Iron Gate Dam tunnel.

Strategic Planning for Future Salmon Releases

The California Fish and Wildlife Department emphasizes that future salmon releases will be strategically planned downstream until the dam's removal.

Dams' Impact on Pacific Northwest Salmon

Zooming out to the broader context of the Pacific Northwest, dams wield significant influence on salmon and steelhead populations. With over 40 percent of the Columbia River Basin's habitat permanently blocked, dams obstruct fish passage between spawning areas and the Pacific Ocean.

Reservoirs Exacerbate the Problem

Reservoirs formed by dams exacerbate the problem, causing detrimental changes in temperature and sediment transport, eliminating crucial spawning grounds. The Hanford Reach of the Columbia River, vital for fall Chinook spawning, faces ongoing challenges due to water level fluctuations caused by upstream dams like Priest Rapids Dam.

Historical Dam Impacts

Historical dam impacts date back to the early 20th century, with splash dams and tributary dams disrupting salmon runs even before the era of mainstem hydropower dams.

Rare Dam Removals: Focus on Rehabilitation

Despite the recognized impact of dams on salmon, removals have been rare, with recent efforts focusing on rehabilitation, such as the inclusion of fish ladders to facilitate salmon migration in dams like the Wallowa Lake Dam.

Governor Newsom's Pledge and Urgent Need for Solutions

As California Governor Gavin Newsom pledges to fast-track dam removal projects to restore salmon access, the interconnected challenges faced by salmon populations across the Pacific Northwest highlight the urgent need for comprehensive solutions to preserve these vital ecosystems.