Gammarus oceanicus Segerstråle, 1947

4. Gammarus oceanicus Segerstråle, 1947 View in CoL

Synonyms: Gammarus zaddachi oceanicus auct.; Lagunogammarus oceanicus auct.

Descriptions and illustrations: Segerstråle 1947, p. 226, fig. 3 a-g; Spooner 1951, p. 130; Dunbar 1954, p. 765, fig. 31; Kinne 1954, p. 414, figs1-2, 4pp; Lincoln 1979, pp 243, 253, figs

100e, 111c, 119.

Biology: Along the south and west coast and in the large fjords of western Norway this is a species of the low intertidal and shallow subtidal, where it is primarily found in the algal belt of Fucaceae and is generally very common. In Northern Norway, and still more characteristically in Svalbard, this species is also very often found under stones in the lower intertidal, even on mudflats with occasional algae-covered large stones ( Weslawski 1994).

Distribution in Norway: This is probably the most numerous Gammarus species on the Norwegian coast, where it also penetrates far into the fjords ( Brattegard 1966, Vader 1977a). G. oceanicus is also common in Svalbard waters, but it is absent from the southern North Sea. It has recently been found further north than earlier in Svalbard waters, probably as a result of global warming ( Węsławski et al. 2018)