Study on reproductive and settlement cycles of Perna perna [Bivalvia : Mytilidae] at natural beds in Ubatuba shore í São Paulo State, Brazil

Abstract

Aspects of the reproductive and settlement cycles of mussels Perna perna (Linnaeus, 1758) were studied at three natural beds in Ubatuba shore, São Paulo State, Brazil (23°26'S; 45°04'W), in order to obtain basic knowledge on the biology of this species, aiming to subsidize its exploitation. It was noted that Perna perna reproduction extends over the whole year, with breeding peaks in January-February (early to middle summer), May to July (middle autumn to early winter) and September-October (early spring). Young mussels larger than 1 mm long, settled on Ulva fasciata, also occurred all the year long. Correlation between spawning and settlement intensities was not observed, but a fair relationship was noted between spawning and young mussel occurrence peaks, 30-60 days afterwards. It is concluded that the mussel spawning in the region studied do not follow a rigid seasonal pattern, making recommendable a permanent control of larval settlement, when it is required the massive captation of young musseIs for purpose of farming.