Lake Washington fish deaths linked to Crosslake rail cathodic protection system

Key points

• WSDOT staff discovered dead fish on August 3 near the I-90 floating bridge, where anode strings from the Crosslake light rail system rest on the lakebed.
• Sound Transit CEO Dow Constantine confirmed a correlation between fish mortality and the cathodic protection system, particularly at the bridge ends where anode strings are clustered.
• An interim mitigation measure was implemented on August 23, lifting 32 anode strings off the lakebed to suspend them in the water.
• Initial findings indicate most dead fish are non-native perch or bass, but several salmon (sockeye, Chinook, coho) were also found, raising concerns due to federal protections.
• Sound Transit states the electrical system poses no risk to humans and has been used globally without harm, but acknowledges the local impact and is pursuing a permanent fix.

Background

The Crosslake Connection, the world’s first light rail line over a floating bridge, opened on March 28, 2026, linking Seattle and Bellevue. The project involved complex engineering to manage stray electrical current from the light rail system, with Sound Transit claiming prior global testing showed no negative impact on fish. This incident follows recent Sound Transit controversies, including a derailment in August 2026 and delays to the West Seattle rail extension.

How outlets are covering it

KOMO and MyNorthwest emphasize the urgency of the investigation and the involvement of dive teams and biologists, while Axios highlights the estimated 2,000 fish deaths since early August. Sound Transit spokesperson Rachelle Cunningham downplays the risk, noting the system’s global use, but acknowledges the need for a permanent solution. WSDOT Secretary Julie Meredith reassures the public that the bridge remains safe for travelers, while The Seattle Times notes that protecting fish from electrical current was a key design requirement from the start.

Why it matters

The incident threatens federally protected salmon populations in Lake Washington and raises questions about the environmental impact of major infrastructure projects. It could lead to regulatory scrutiny, potential fines, or delays in future Sound Transit expansions. The state has already invested $1 billion in fish passage projects, making this a significant setback for conservation efforts.

What to watch

Sound Transit is monitoring the area and aims to implement a permanent solution in the coming weeks. Further analysis of dive team photos will determine if the interim fix resolved the issue. Regulatory agencies and Tribal fisheries managers are involved in the investigation to ensure long-term protection for fish populations.