Sea salmon are relocated in upper reaches of northern Iijoki river past chain of power plants

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This summer 50 salmon of reproductive age will be placed in the Korpijoki and Livojoki rivers, which are tributaries to the larger Iijoki river in the Province of Oulu in Northern Finland.
      Next year and the year after that, 150 salmon individuals will be relocated into these upper reaches past the five hydroelectric power plants on the lower course of the Iijoki river. For decades, the power plants that were built between 1961 and 1971 have prevented the migrating fish from entering into their traditional spawning areas.
     
The relocated large fish, which each carry a small radio transmitter to enable their progress to be monitored online, have already caused some astonishment among the residents living by the river branches. Nearly 50 years have elapsed since the last time salmon were seen swimming in the upper reaches of the Iijoki.
      The salmon are now hoped to breed in the area where there are at least 600 hectares of suitable spawning waters. “This way – for the first time in decades - we would get naturally-spawned salmon from the Iijoki river back into the Baltic Sea”, explains the supervisor of the undertaking, Arto Hirvonen from the North Ostrobothnia Regional Environment Centre, NOREC.
     
In Finland the majority of the naturally-spawned migrating salmon that manage to make it to the sea come from the still free-flowing Tornionjoki and Simojoki rivers, which both empty into the Bay of Bothnia, the northernmost part of the Baltic Sea.
      On the Swedish side there are half a dozen such rivers.
      Of the over seven million young migrating salmon in the Baltic Sea, around 35 per cent are naturally spawned in the area’s rivers. Of the commercially caught salmon, about 70 percent are naturally-spawned.


Previously in HS International Edition:
  Sharp decline in large female salmon in Teno River (25.8.2009)

Links:
  Tracking of the Iijoki salmon (in Finnish)

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