Reproductive strategy of the common star fish, Astropecten polyacanthus (Echinodermata: Asteroidea) from Suez Canal Lakes, Egypt

Specimens of the star fish, Astropecten polyacanthus were collected monthly from the Great Bitter lakes and Lake Timsah during the period from1999 to 2001. Individuals of A. polyacanthus showed a sex ratio (males to females) of 1:1.34 and 1:0.97 in Great Bitter lakes and Lake Timsah respectively. The examination of reproductive data showed that individuals of A. polyacanthus spawned all the year around with peaks during spring and autumn. Oocyte size frequency distribution was similar in both lakes and the egg size ranged from 8 μ to 90 μ. All different sizes of oocytes were found all the year around with different proportions. Maximum fecundity (oocytes / female) reached 4800000 at Great Bitter Lakes and 7465860 at Lake Timsah. Fecundity showed exponential increases with the increase in body size, body weight and gonad weight.