Fecundity and reproductive effort of sea scallops Placopecten magellanicus from the Gulf of Maine

Abstract

[Production of reproductive tissue, measured as △ weight pre- and postspawning in 1982 and 1984, is exponentially related to shell height in the sea scallop Placopecten magellanicus (Gmelin). Similarly, egg number is an exponential function of shell height with egg production beginning at Age 1. Estimated mean egg diameter is 66.8 ± 1.6 μm and calculated egg weight is 1.6 × 10⁻⁷ g. Age-specific reproductive production (Pᵣ) increases with scallop age. In 1984, somatic production (Pg) steadily increased up to Age 5 and then remained relatively constant. Reproductive effort in 1984 was an increasing function of age. Based on observations of the degree of spawning synchrony in 1979, 1982 and 1984 it is suggested that sea scallops may switch annually from a synchronous spawning in some years to a protracted spawning period depending upon environmental conditions. Thus, year-class success may correlate with the degree of spawning synchrony, rather than total reproductive effort or fecundity.]