The reproduction of Ecteinascidia turbinata was studied in Punta del Este, Isla de la Juventud, Cuba. Gonadal development of 4 606 zooids ftom 30 colonies was studied in six localities by monthly samples ftom June 1994 through May 1995. In addition, ftom August lO November 1997, the regenerating capacity of the colonies was assessed. Number and diameter of oocytes, embryos and larvae were measured in 21 zooids (17- 23 mm long). Five stages of gonad development are described: juvenile, immature, mature, in larval release and in reabsorption. The zooids reach 27 mm in length. Immature zooids may exceed 60 % of the total population throughout the year and prevail in most length classes. Minimum size for mature zooids was 6.7 mm, but more than 50 % of mature and at larval release zooids measured 19-20 mm. Sexual reproduction occurs ftom September through July with a peak in April-May. Asexual reproduction occurs year-round, but more intensely during the summer, especially in Augusl After the spawning and reabsorption of all zooids in a colony, the following cycles of generation-degeneration of the colony repeat approximately every 40 days
Keywords: tunicate, ascidian, reproduction, armual variations