Quantitative allometry of gamete production by Mercenaria mercenaria into old age

Abstract

Among 67 hard clams Mercenaria mercenaria collected during spawning on 4 June 1982 from Core Sound, North Carolina (USA), gonadal mass increased significantly with body size (shell length and internal volume). Clam age did not explain a significant amount of the residual variance in the linear regression of log gonadal mass on log shell length. Because this collection contained 11 individuals over 24 yr of age, including the oldest M. mercenaria ever reported at 41 and 46 yr, these results imply that gamete production in M. mercenaria continues into old age at a quantitative level predicted simply by the power curve relating gonadal mass to body size. There was no suggestion of even partial reproductive senility in gamete production at old age. Exponents in the 2 power curves relating gonadal mass to shell length (3.1) and shell volume (1.1) did not differ significantly from those expected under isometric growth of gonadal mass.