Chondracanthus chamissoi (Rhodophyta, Gigartinales) in northern Chile: ecological aspects for management of wild populations

Abstract

Abiotic and biotic factors affecting seasonal variations in the biomass andreproductive condition of Chondracanthus chamissoi were evaluatedin a population at La Herradura Bay, northern Chile. During spring,increase in temperature, light, and photoperiod favored the reproductiveactivity of C. chamissoi, contributing to its growth and production ofreproductive biomass. During summer, extremes of temperature and lightavailability were accompanied by bleaching of the thalli, followed bydecomposition and biomass loss, significantly lowering production.Epiphytism and herbivory showed were then at their maximum. Analysis offertility showed that C. chamissoi was in reproductive conditionthroughout the year, with maximum for cystocarpic and tetrasporic plantsduring spring, significantly correlated with total biomass production.Production and liberation of spores and other values for reproductivecapacity showed the highest values in spring. The results of the study,coupled with information from the literature, recommend two commercialharvests during spring, at a time when standing crops are the highest, andvalues for reproductive condition predict adequate expression of the sexualphase. The time of the year suggested as adequate for commercial harvestof this alga probably coincides with the highest quality of its carrageenans,and would precede the phase of local growth cycle, where its biomassbegins to deteriorate due to bleaching, epiphytism and herbivory.