Comportamento reprodutivo de Mussismilia hispida (Verril, 1902) (Cnidaria, Anthozoa, Scleractinia)

Abstract

Through histological analysis the reproductive pattern of Mussismilia hispida, a zooxanthellate coral species endemic to the Brazilian coast was verified. Fragments from 2 tagged colonies, which were marked in the field in order to be repeatedly sampled, and 10 others haphazardly chosen were collected monthly, from April/89 to March/90, at Praia da Tartaruga, Buzios, Rio de Janeiro. The results showed that M. hispida is a sequential hermaphroditic species with a broadcast-spawning mode of reproduction, and external fertilization and development. Female cells developed prior to male cells, and were first observed in April/89. Size of Stage I oocytes partially immersed into mesogleal layer ranged from 13,04μm to 19,56μm. Between February/90 and March/90, oocytes reached maximum ripeness and were ready for fertilization. The largest Stage Ili oocyte found in this period had 521,76μm. The spermatic cycle began in December/89 and continued through March/90. Mature oocytes and cysts occurred concomitantly on the sarne fertile mesenteries during summer, and disappeared from some samples between February/90 and March/90. Gonad maturation occurred with increasing sea-water temperature, evidencing seazonal synchrony in the reproductive cycle. Histologically, an intercolonial asynchrony in the development of the gametes during the breeding season was observed. From this, it was possible to infer that different colonies of the population reproduced at different times throughout the spawning period. No zooxanthellae were found in pre-spawning oocytes, which characteristically had a large amount of vitelline material and a peripheral germ vesicle.