Amphipod fauna of the sponges Halichondria panicea and Hymeniaci-don perleve in Lough Hyne, Ireland

Abstract

ponges Halichondria panicea (Pallas) and Hymeniacidon perleve (Montagu) were col- lected over 12 mo from 2 sites in Lough Hyne (Ine), southwest Ireland. The associated amphipod fauna was identified and species comparisons were made between sponge species and sites. The number of species was similar in both sponges and at both sites, but considerably higher than that described from other places. Most species differed significantly in their relative abundance between sponges and sites. Two species, Leucothoe spinicarpa and Perrjerella audoujniana, were inqullinous in both sponges, while the other 30 species were epifaunal. The relationship between the sponge and the inquiline amphipods may be parasitic, and that with the epifaunal amphipods mutualistic. Over 70% of the amphipod fauna of both sponges at both sites was made up of Caprella acanthifera, Microdeutopus anomalus, Corophium bonnellii, and Lembos websteri. The dominant species differed between sponges and sites, but the level of dominance and species rank abundance was similar in both sponges and at both sites. The relationship between dominance and species richness, as descriptors of assemblage structure, is discussed.