Abstract
Laboratory experiments were conducted to measure prey selectivity of the fringed filefish M. ciliatus. Prey included 3 spp. of gammarid amphipods: Elasmopus levis, Melita appendiculata (Melitidae) and Lembos unicornis (Aoridae). The relative vulnerability of these species to predation was determined to be a function of their frequency of encounter. L. unicornis, a strikingly pigmented species, was disproportionately consumed by filefish when placed in experimental aquaria with equal numbers of either E. levis or M. appendiculata. This species was probably encountered more frequently and thus was more accessible to predation owing to its unique pattern of pigmentation. Results of these experiments were consistent with field data on selectivity of M. ciliatus.