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

Abiotic and biotic factors affecting seasonal variations in the biomass and reproductive condition of Chondracanthus chamissoi were evaluated in a pop ulation at La Herradura Bay, northern Chile. During spring, increase in tem perature, light, and photoperiod favored the reproductive activity of C. ch amissoi, contributing to its growth and production of reproductive biomass. During summer, extremes of temperature and light availability were accompa nied by bleaching of the thalli, followed by decomposition and biomass loss , significantly lowering production. Epiphytism and herbivory showed were t hen at their maximum. Analysis of fertility showed that C. chamissoi was in reproductive condition throughout the year, with maximum for cystocarpic a nd tetrasporic plants during spring, significantly correlated with total bi omass production. Production and liberation of spores and other values for reproductive capacity showed the highest values in spring. The results of t he study, coupled with information from the literature, recommend two comme rcial harvests during spring, at a time when standing crops are the highest , and values for reproductive condition predict adequate expression of the sexual phase. The time of the year suggested as adequate for commercial har vest of this alga probably coincides with the highest quality of its carrag eenans, and would precede the phase of local growth cycle, where its biomas s begins to deteriorate due to bleaching, epiphytism and herbivory.