The colourful protest to highlight claims of environmental damage caused by Scottish Power's subsidiary Pacificorps has gone ahead even though the sale of the company's US wing was announced in May.

The noisy protest outside Scottish Power's headquarters comes just two days before the company's annual meeting where the tribes will claim Pacificorp has destroyed fishing rights, its dams blocking hundreds of miles of salmon spawning grounds through ancestral land. They want the dams scrapped.

Geoff Mitchell from the Klamath-Mordoc tribe said: "We still have people at home that are suffering, that are dying because of a lack of fish. No fish make it to my county and all because of dam blocking."

The five billion pound purchase of Pacificorp by US giant Mid American will take 18 months to go through. They claim a personal commitment from the chief executive of Scottish Power was made last year to find a solution to the huge decline in fish stocks on the salmon rivers.

Larry Hendrix from the Urok tribe said: "This is some of the fish kill that happened three years ago, over 60,000 fish dead from bad water quality and quantity. They didn't create the problem. They inherited it when they bought it. Whether they knew about the problem, I don't know. They should have."

Mike Orcutt from the Hoopa Valley tribe added: "They are the company. They are the people that are the company and they are the people that can resolve this issue in the small amount of time that now exists."

No one from Scottish Power was available for interview. The company insists it's an American affair and must be resolved there.