The life cycle and productivity of an intertidal population of the amphipod ampelisca brevicornis

This paper describes the life cycle of Ampelisca brevicornis (Costa) at Derbyhaven beach, Isle of Man. The species was a univoltine annual, with breeding extending from May to September. Recruitment commenced in July. Mature males occurred from April to August with a peak in May when they were captured in the plankton at night. The annual production ranged from 1·31 dry weight m −2 (12·54 kJ m −2) to 1·68 g dry weight m −2 (18·98 kJ m −2) with a P: B ratio of 2·49 to 3·21. A substantial part of this production is probably consumed by young flatfish. These results are compared with data from sublittoral populations of Ampelisca elsewhere.