On the Pacific coast of North America, there are five species of Salmon, with very different habitat requirements as juveniles. Pink Salmon, for example, migrate to the sea straight after hatching. Coho Salmon either migrate directly to sea after hatching or move into pools in late Summer. While such pool-livers can benefit from Beaver ponds, this can only happen if Beaver dams do not restrict the access of the adult Coho (see www.skeenafisheries.ca/Beaver%20Dam%20Breaching%20Program%202004.pdf  for an example of this happening). On the East coast of North America, there are Atlantic Salmon and the best study of the effects of Beaver dams on Salmon migration comes from that area (Mitchell & Cunjak, 2007). In this study, it was found that the complex of Beaver dams on the small tributary of the Miramichi (a major Canadian Salmon river) either totally or partially restricted spawning Salmon access in all but two out of 14 years, when the Autumns were particularly wet.

There are many reports on the sort of problems caused by Beaver dams in North America (to roads and forestry as well as fisheries) that can be found online bv searching for “Beaver” and “fish passage”. or “Beaver” and “Culverts” for example.

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