According to Parker & Ronning (2007) Beaver have not yet colonized the main Salmon and Sea-trout areas of Norway, in the northern and western areas but are still confined to southern and eastern area. This is supported by the distribution map of Beavers in Norway given in Halley & Bevanger (2005).

In the Norwegian Salmon catch statistics for 2007 (Official Statistics of Norway, D 397) the provinces with the longest established / original Beaver populations (Vest-Agder, Aust-Agder, and Telemark, in the South & East of the country ) give, in fact, only the 6th, 14th and 15th ranking provincial catch totals out of the 16 salmon provinces of Norway. This does not suggest any great overlap between mature Beaver populations and Salmon fisheries.

According to a report published Online, on the 7th February 2008, by the Norwegian Pollution Control Authority: “Acid rain has wiped out salmon in all the larger salmon rivers in the southernmost counties(= provinces)”. This being the case, it must follow that the scope for impacts of Beavers on Salmon in those southernmost provinces must be much reduced.

These same provincial catch statistics show that only one Norwegian province, Finnmark, in the extreme North, caught more Salmon than the River Tweed alone in Scotland. It has to be recalled though that some thirty Norwegian rivers on the West coast have lost their Salmon through the parasite Gyrodactylus salaris and those on the South have lost populations to Acid Rain. While these factors must depress Norwegian catch totals, the fact that a single Scottish river can catch more Salmon than all but one Norwegian province suggests very different situations.

The physical differences between Scottish and Norwegian landscapes also have to be remembered. The paper by Parker & Roenning (2007) entitled “Low Potential for the Restraint of Anadromous Salmonid Reproduction by Beaver, Castor fiber, in the Numedalslagen catchment, Norway“ has been widely quoted as showing that Beaver pose no problems for spawning salmonids there and so would not be a problem in Scotland. However, it is made very clear in the paper itself that the topography of the study river (the Numedalslagen) is very different from that of typical Scottish East-coast Salmon river in that it occupies a steep “U-shaped” glacial trough in which Salmon can only use the main channel and the small sections of the tributaries that flow between the main river and the valley sides, the side streams being either too steep beyond the valley walls or having waterfalls there. This means that there is very little potential for Beaver impact on salmonids. This is a very different situation from a major Scottish, East-coast Salmon river, where the flatter landscape allows Salmon to penetrate far upstream in smaller tributaries. This difference between the Scottish and Norwegian situations is specifically made in this paper itself, where the authors say: “As Scottish salmon appear to regularly use the headwaters of small streams for spawning to a greater degree than salmon in south-central Norway and Sweden, beaver dams there could have a greater potential effect on spawning activity than that observed in our study.”

Whilst this paper has been prepared by The Tweed Foundation on the basis of information that it believes is accurate, any party seeking to implement or otherwise act on any part or parts of this paper is recommended to obtain specialist advice. The Tweed Foundation does not accept responsibility under any circumstances for the actions or omissions of other parties occasioned by their reading of this paper.