INPACT OF BEAVER (CASTOR FIBER) BUILDING DAMS ON SALMON FISH MIGRATION IN ŽEIMENA RIVER BASIN

Abstract

The basin of the Žeimena River is of great importance for the migration of salmon fish, which is why an ichthyological reserve was established here in 1974. Due to the increasing abundance of beavers in the tributaries of the Žeimena River, where the construction of artificial dams is prohibited by law, migrating fish are increasingly encountering dams built by beavers. It was established that this conflict is relevant in those river sections where the water flow falls within the range of 0.5-4.0 m3/s. It was also established that individual beaver dams do not have a negative impact on river sections falling within this interval, but if there are more than two dams, the rest should be dismantled.