Marine isopods are the ancestors of the harmless herbivorous woodlouse species often found in piles of leaves. In contrast to woodlice, marine isopods of the family Cirolanidae (cirolanid isopods) are scavengers and predatory carnivores that form swarms and can cause damage to fishing and aquaculture industries. Furthermore, these animals are known to bite swimming and diving humans and therefore may have negative effects on recreational activities in areas where swarms form. One cirolanid isopod species, Cirolana harfordi, displays social behaviour, an attribute that may facilitate the formation of swarms. This species gives live birth, a highly unusual mode of reproduction for an invertebrate and isopod. The rate of viviparous reproduction in C. harfordi is sped up by warmer conditions, indicating the threat that cirolanid isopods pose to ocean resources may intensify with global warming.
Murray Thomson (Wed,) studied this question.