ANNUAL REPRODUCTIVE-CYCLES OF 3 SYMPATRIC SPECIES OF INTERTIDAL HOLOTHURIANS (ECHINODERMATA) FROM THE COAST OF THE EASTERN CAPE PROVINCE OFSOUTH-AFRICA

Seasonality of reproduction of Roweia stephensoni, Pseudocnella sykion and Neostichopus grammatus was compared using gonad indexes, gonadal tubule diameters, egg diameters and the abundance of spermatozoa in tu bules from January 1992 until August 1993. All three species were dioe cious and the populations studied did not deviate from a 1:1 sex ratio . Body sizes at first sexual maturity were 2.5-2.9 cm(3) for R. stephe nsoni and P. sykion and 3.0-3.9 cm(3) for N. grammatus. The gonads of R. stephensoni and P. sykion consisted of a group of unbranched tubule s of equal diameter, with males having more tubules of a smaller diame ter than females. By contrast, the gonad of N. grammatus consisted of two tufts of multiple branched tubules. All three species had annual r eproductive cycles, and in R. stephensoni and P. sykion gametogenesis occurred from March 1992 until August/September 1992, and gonad maturi ty was maintained until spawning in January 1993. By contrast, in N. g rammatus gametogenesis occurred from July 1992 until September 1992, a nd gonad maturity was maintained until spawning in December 1992/Janua ry 1993. In R. stephensoni and P. sykion gonads never completely regre ssed whereas in N. grammatus gonads regressed after spawning.