Occurrence of the European eel in lakes in the northern part of its distribution area is limited to low-altitude coastal areas, likely due to topographical conditions

Abstract

With the decline of the European eel, protection measures in all parts of the eel’s distribution area may be increasingly important. Norway has a vast coastline (58°–71°N), but the distribution of eel has been largely unknown. We analysed data from questionnaires on fish distribution, covering 30 575 Norwegian lakes. Eels were recorded in 1773 lakes. The distribution was largely restricted to low altitude lakes in coastal areas (95% of the lakes with eels were situated below 295 m a.s.l., and within 87 kilometres from the sea). The occurrence of eels decreased towards the north, and only 5% of the lakes with eel were located north of 64.5°N. The northernmost lakes with eel were at 70.6°N, in the Barents Region. The degree to which man-made migration barriers restrict the distribution of the European eel in Norwegian freshwater should be further researched and data on the eel life history and densities are also largely missing.