Gonadal Maturation and Artificial Spawning of the Grooved Carpet Shell Clam, Ruditapes decussatus from Timsah Lake, Suez Canal, Egypt

Abstract

Culture of clams is clearly limited by the availability of natural seed (Ojea et al., 2008; Da Costa et al., 2020). Therefore, bivalve spat from hatchery is currently the only sustainable alternative for the support of aquaculture activities )Ojea et al., 2008 ; da Costa et al., 2012). Hatcheries are important to reinforce natural recruitment to restock natural beds which are threatened by over-fishing.To improve the methods of cultivating this clam, detailed knowledge of the gonadal development and spawning periods is fundamental. Knowledge of gametogenesis would help hatchery managers to determine the best strategy to produce larvae with high quality and quantity. Thus, this information may help to regulate the collecting time, management and protection of natural clam stocks (Serdar et al., 2010) Sexual maturity of clams depends on size rather than age or geographic distribution (Ojea et al., 2004). The sexes are generally separate, and sexual maturity is generally until fully matured, but this development has been divided into several maturity stages, e.g. resting, developing, mature, partially spawned and spawned (Delgado & Pérez-ARTICLE INFO

Artificial Spawning and Gametogenic Development of the Black-Lip Pearl Oyster, Pinctada margaritifera Linnaeus, 1758 (Bivalvia: Mytilidae) in Mabahiss Bay, the Red Sea

“…The current research used a numerical grading approach to estimate the gonad index, which was determined by assessing the maturity stages of pearl oysters, based on the gonadal development according to the formula presented by (Yigitkurt, 2021). The high values of the gonad index were synchronized with the maturity of the gonad, while the lower values seen after the high values were an indicator of spawning (Sami et al, 2021). Monthly variations of gonad index values of males and females followed virtually the same pattern, and the gonad index values for P. margaritifera confirmed the behaviour of maturity phases.…”

“…In several species of bivalves, serotonin has been shown to stimulate the spawning process successfully. (Gibbons and Castagna, 1984;Sami et al, 2021;Nowland et al, 2021).…”