Some observations on the populations of Mysis relicta in Lough Neagh

Within the British Isles, the occurrence of Mysis relicta Loven is restricted to relatively few lakes and rivers (Tattersall and Tattersall, 1951). Two large lakes, Lough Neagh and Lough Erne, containing this species are to be found in Northern Ireland. The presence of Mysis in Lough Neagh has been known for a long time and a description of its collection and diurnal behaviour and speculation as to its origins in freshwater ecosystems appear in the early description of the lough by Dakin and Latarche (1913). They suggest that Mysis, often considered to be a benthic form, ‘paradoxically is as important a plankton form as any other species of plant or animal caught in the lake’. Since then its presence in the lough has been referred to by a variety of workers including Tattersall and Tattersall (1951), Holmquist (1959) and Gledhill et al. (1976).