Introduction of non-native species of Kappaphycus (Rhodophyta, Gigartinales) in subtropical waters: Comparative analysis of growth rates of Kappaphycus alvarezii and Kappaphycus striatum in vitro and in the sea in south-eastern Brazil

Abstract

SUMMARY We compared the growth rates of Kappaphycus alvarezii (Doty) Doty ex P. Silva and Kappaphycus striatum (Schmitz) Doty, both, in vitro under different conditions of light and temperature, and in the sea. Temperature was the most important factor controlling the growth of both species, in vitro and in the field. In the sea there was a clear seasonal pattern in growth rate, attributed to temperature and salinity variation. The lower growth rates were registered in winter and spring, and the highest in summer and autumn months for both species. Based on growth rate in the field, and the production of viable tetraspores during the summer in Kappaphycus striatum, we conclude that is more profitable, and ecologically safer, to only continue with the introduction program of Kappaphycus alvarezii.