INVESTIGATIONS ON BROOD PROTECTION IN PSOLUS-DUBIOSUS (ECHINODERMATA, HOLOTHUROIDEA) FROM ANTARCTICA IN SPRING AND AUTUMN

Brood protection in the holothurian Psolus dubiosus Ludwig and Heding, 1935 was investigated in the Antarctic zone of permanent packice, an environment with an extreme seasonality in planktonic activity. Yearly reproductive cycles on the continental shelf of this area have been poorly investigated. Brooded juveniles of this species were found for the first time between the retracted tentacles of adult females at two different localities in the southeastern Weddell Sea, sampled in spring (October 1986) and autumn (February 1984). Mean lengths of the juveniles of each brooding female showed significant differences within each sample. However, there was no detectable difference in size of the juveniles between the two seasons. The results are discussed as an uncoupling of the dynamics of the early life history of these benthic invertebrates in space and time from processes in the euphotic layer of the Southern Ocean. The species investigated follows the general trend of some Antarctic invertebrates towards a non-pelagic development.