Reproductive cycles of Diadema setosum and Echinometra mathaei (Echinoidea: echinodermata) from Kuwait (northern Arabian Gulf)

A study was undertaken on the seasonal variations in the reproductive biolo gy of Diadema setosum and Echinometra mathaei from the coral reefs of Kuwai t. Sixteen monthly samples were taken for both species and gonads were proc essed for histological studies. Both species had peak spawning in summer mo nths when maximum seawater temperature was between 24.2 and 28.8 degreesC. Peak spawning was seen for Diadema in April-May (24-28 degrees%), while thi s point for Echinometra was achieved in June (28.8 degreesC). The spawning peak was much broader for Diadema. The breeding season in both species coin cided well with increasing seawater temperature and day-length. The gonad c olor was not related to sex and there was no difference in drained weight o f male and female of both the species. Both spermatogenesis and oogenesis w ere histologically similar to other echinoid species described by other aut horities.