Larval settlement of the mussel Perna perna (Linnaeus, 1758) on natural and artificial substrata at Ubatuba, SP

Abstract

The fixation intensity of plantigrades of the mussel Perna perna (Linnaeus, 1758) on two natural banks of Sargassum cymosum (Agarth) and on artificial substrata (nylon screen suspended in a raft mussel culture) was registered with the purpose to detect the occurrence of an annual pattern of variation, as well as to establish the best periods to lay artificial collectors in the coast of Ubatuba, São Paulo State, Brazil. Fixation intensity, temperature and salinity were observed at intervals of 14 days, from July, 1985 to June, 1988. Temperature and salinity data did not reveal considerable differences among sampling stations. Fixation data pointed out a continuous fixation of plantigrades throughout the years; an annual pattern of variation was not observed. Higher fixation occurred in the spring, followed by the autumn and winter, so that these are considered the best periods to lay artificial collectors.