Age determination and shell growth of Chamelea gallina (Bivalvia: Veneridae) in the western Mediterranean

Abstract

Widely spaced growth bands are formed in winter and late spring between January-June, whilst narrow growth increments are deposited in summer and early autumn between August-October, following the maximum summer seawater temperature. The warm summer seawater temperature of 33°C in the W Mediterranean may be responsible for the suppression of shell growth, as evidenced both by the narrowing of the growth increments and by the later appearance of clefts in shell sections. The annual pattern of narrow and wide growth increments was used to estimate the age of C. gallina and to construct growth curves for this species from the E coast of Spain. Growth curves for the clams, determined from the internal microgrowths bands and from the spacings between the clefts in shell sections, differed from the curve calculated using surface growth rings. -from Authors