Relationships between the nudibranch madrella sanguinea and its broadly-distributed prey, the bryozoan mucropetraliella ellerii

Abstract

The nudibranch Madrella sanguinea (Angas) occurs and feeds almost exclusively on the encrusting cheilo- stome bryozoan Mucropetraliella ellerii (MacGilliv- ray). The bryozoan occurs in a range of subtidal and intertidal habitats, which, inter alia, vary in exposure to air and wave action, density of bryozoan colonies, and presence of other organisms. The abundance of Madrella sanguinea varied markedly between 13 sites that were surveyed regularly, but nudibranch abundance was not associated with particular habitats or particular geographic locations, and there was no significant correlation between nudibranch abundance and bryozoan colony abundance. In the field, nudibranchs did not occur on..