Gonadal growth and reproduction in the sea urchin Sphaerechinus granularis (Lamarck 1816) (Echinodermata: Echinoidea) in southern Spain
Inés Martínez-Pita, Ana I. Sánchez-España and Francisco J. García
The gonadal index and reproductive state of the sea urchin Sphaerechinus granularis were studied for a year in three populations from southeast Spain. The development of the gonad during the period of study was assessed using histological methods and four maturity stages were considered for female specimens and two for male specimens. The study of gonad development showed a clearly defined annual cycle of gametogenesis with a single spawning period in summer-autumn. It begins in June at Torremuelle and Palmeral and a month later at La Herradura. The three populations exhibited similar reproductive patterns, having mature gonads in almost all the months. Though the environmental conditions were similar, the population from La Herradura had the highest Gonadosomatic Index value (GSI) and that from Torremuelle the lowest one.