More information about impacts on salmon spawning:

Sakhalin Energy has used techniques which are not considered by salmon experts or even by Shell itself to be best practice: unapproved stream diversion, inadequate erosion control measures, and the pollution of salmon spawning rivers with sediment.

Salmon needs crystal clear water for its spawning. Suspended solids (muddy waters) prevent salmon females from spawning, because they destroy biological connections between the salmon. Dispersed sediments also prevent the survival and development of salmon eggs.

Useful links:

Wild Salmon Center