Abstract
The gonad index of Ctenodiscus crispatus from Ramfjorden, northern Norway, varied slightly during the year, consistent with a main reproductive period during midwinter (December–January). This conclusion was supported by observations of planktonic larvae and young starfishes in the area. Compared with other asteroids, the gonads of C. crispatus were relatively small throughout the year. Oocytes in various developmental stages were found in the ovaries throughout the year as well as active sperm in the testes. Large, nearly mature oocytes, were most numerous in late autumn and midwinter. Biochemical studies showed an increasing amount of lipid as well as protein in the ovaries during late autumn. Total values, although varying, reflected probably the accumulation of nutrient reserves as well as growth of gonads during certain periods of the year. The content of lipid was high in ovaries, this constituent being the main energy reserve in ovaries and eggs. Ultra-structural studies of oocytes illustrated the high lipid content.