BIOTIC Species Information for Spisula solida
|Researched by||Lizzie Tyler||Data supplied by||University of Sheffield|
|Refereed by||This information is not refereed.|
|Reproductive Season||February to June||Reproductive Location||Insufficient information|
|Reproductive frequency||Annual protracted||Regeneration potential||No|
|Life span||6-10 years||Age at reproductive maturity||1 year|
|Generation time||Insufficient information||Fecundity|
|Egg/propagule size||Fertilization type||Insufficient information|
|Reproduction Preferences Additional Information||Longevity
The life expectancy of Spisula solida is up to approximately ten years (Fahy, 2003).
Spisula solida reaches sexual maturity during its first year, which is a function of age, not of size (Gaspar & Monteiro,1999; Fahy et al., 2003).
The sexes of Spisula solida are separate and there are no records of hermaphrodites (Gaspar & Monteiro, 1999). Male and female white clams are distinguishable externally since the colour of the gonad in this species is reddish in the females and yellowish-orange in the males (Gaspar & Monteiro, 1999). Both sexes show a synchrony in gametogenic development and spawning.
Gaspar & Monteiro (1999) observed that gametogenesis in Spisula solida began when the seawater temperature started to decrease (late September). Gaspar et al. (1999) concluded that the initiation of gametogenesis in Spisula solida was a response to falling temperature and that spawning occurred when the temperature began to rise rather than occurring at a fixed temperature. The maturation of the gonad continued until late January when the water temperature was at its lowest (Gaspar & Monteiro, 1999). In Danish waters specimens of Spisula solida were sexually inactive from July-Sept. The first ripe stage of gonads was reached in December, and all individuals were ripe by January (Gaspar & Monteiro, 1999).
Spawning begins in February (Gaspar & Monteiro, 1999). Gaspar & Monteiro (1999) noted that 75% of a studied population were in the spent stage of their gametogenic cycle by June (Gaspar & Monteiro, 1999).
Ford (1925) suggested that Spisula solida can be moved along by water movement (bed load transport) along the sea bottom to another position on the seabed. Therefore, in the course of time considerable mixing could easily bring together individuals of different ages and origins (Ford, 1925).
In Ireland the recruitment of Spisula solida is irregular with 1 year old clams out numbering all the other year classes (Fahy et al., 2003). The reasons for this are unknown. However, irregular settlement rather than erratic gamete production might be the explanation for the occasional strong representation of a year class in Waterford Harbour clam population (Fahy, 2003).
|Reproduction References||Gaspar & Monteiro, 1999, Ford, 1925, Fahy, 2003, Fahy et al., 2003,|