When  hydro power plants were built the salmon spawning grounds and migration routes were destroyed. At the first power plant, the Lower Tuloma, a fish ladder was built. Within a few years salmon catches soon approached their former levels.
At the time when hydroelectric plants were constructed, salmon breeding areas and migratory routes were disrupted. A fish ladder was set up at the first plant, the Lower Tuloma. In just a couple of years, salmon catches returned to their former numbers.