Previously salmon had taken advantage of different types of topography to adapt to natural disasters. Today there are no pools for them to escape to, and when heavy rains come the fish are washed downstream. No fish, no matter how strong, can overcome the meters-high dams to get back upstream, so they are left to die from the higher water temperatures downstream.
過去鮭魚利用不同地形，衍化出可以適應自然災害的方法，如今缺乏深潭可躲，大雨來，被沖往下游，面對十幾公尺高的攔砂壩，再壯碩的魚兒也不可能如跳高選手，只能留在炎熱的下游，活活熱死。