Estados tempranos de Echinoidea en canal Lagreze, Islas Guaitecas, sur de Chile

Abstract

The limited publications on the dynamics of Echinoids on the coast of Chile, despite its ecological significance to marine benthic communities, have hindered the understanding of the importance of this group on benthic communities and the proposal of appropriate conservation and management measures. The objective of this work was to study the vertical and temporal variability of early stages of Echinoids during spring-summer period in a southern channel of southern Chile and associate it, in the particular case of Loxechinus albus, with the reproductive status of adults individuals. For this, i) daily samples of plankton in three depth strata were collected, every 15 days from October 2005 to February 2006, ii) post-settlers on artificial substrates were monitored and iii) the gonad somatic index was obtained for adult specimens of L. albus. Planktonic larval stages of Arbacia dufresnei, Loxechinus albus, Pseudechinus magellanicus and Ophiuroidea, were identified, as well as Ophiuroidea and L. albus post-settlement. Larvae of L. albus in plankton coincided with a decrease of gonad index in adults of this species, whereas post-settlers were observed 15 days after the longest period of larval density in the plankton. Although information on A. dufresnei and P. magellanicus reproduction in adults was not collected, autumn-winter period has been reported as the period of maximum larval abundance. Echinoids larvae were observed in restricted periods, more frequently on the sea surface at night and in low density compared with previous studies.