1. Gammarus locusta (Linnaeus, 1758)

Descriptions and illustrations: Sexton 1942, pl. 3 figs 19-24; Spooner 1947, p. 7, figs 1, 2 A-B, 3; Kinne 1954, p. 409, figs 1-2pp, 4-6; Stock 1967, p. 11, fig. 1.

Ecology and habitat: A marine, mainly sublittoral species of the algal belt, tolerates some lowering of the salinity, but not much, unless it is stable, as in the Baltic. Not often found in the intertidal during ebb. A useful review is Costa & Costa (2000)

A very special case was the situation in Rauneforden near Bergen, where large amounts of kelp (mainly Laminaria) washed down to the bottom at 240 m. In this biotope Gammarus locusta was surprisingly common, and the animals grew very large (Vader, unpubl. obs.).

Distribution in Norway: Not really well known because of earlier confusion, mainly with G. oceanicus, and the fact that this species mainly lives on the outer coast and largely sublittorally. Occurs quite commonly along the entire South and West coast, much more sparingly east of the North Cape. It does not penetrate into the fjords much, and in the North it is restricted to the outer coast. Surprisingly, recent studies have found the species present in Kongsfjorden, Svalbard (Berge & Shunatova, pers. comm.)