Ice Plug Causes Fish Kill

An intake pipe plugged with ice early on Friday morning, March 28, resulted in the death of almost 200,000 young spring Chinook salmon at a Clearwater Fish Hatchery satellite facility on the Lochsa River. The plugged intake pipe feeds the acclimation ponds at the Powell facility, holding spring Chinook smolts that were to be released into the Lochsa River later that same day. Smolts are juvenile salmon ready to begin their migration to the ocean. The loss of 192,153 salmon smolts represents 46.2 percent of the spring Chinook smolt release from the Powell facility this spring. The rest of the young fish to be released from Powell already had left the pond by themselves during the last few days before the incident. Hatcheries in the Clearwater basin produce about 4.4 million smolts annually. About midnight of March 27, the temperature dropped below 20 degrees. In response to a precautionary alarm, a hatchery attendant checked the intake and cleared away slush ice but did not check it again until between 6 and 7 a.m. In the interim, ice had blocked the intake, completely shutting off the flow of water to the acclimation pond. Unusually cold weather led to the ice formation that plugged the intake pipe. Normal operations call for regular clearing ice from the intake during cold weather. But human error allowed the plugged pipe to go unnoticed long enough to result in the fish kill. Appropriate disciplinary action has been taken, and Fish and Game has reviewed current operational protocol to reduce the possibility of this happening again. The Powell satellite facility and the Clearwater Hatchery are part of the Lower Snake River Compensation Plan, a federal mitigation program created to provide mitigation for fish losses caused by the construction of the four federal dams on the lower Snake River. Fish and Game operates the hatchery with funding from the U.S. Fish and Wildlife and Lower Snake River Compensation Plan office.