Evidence of a semiannual reproductive cycle for the sea scallop, Placopecten magellanicus (Gmelin, 1791), in the Mid-Atlantic region

W. D. duPaul, Virginia Institute of Marine Science
J. E. Kirkley, Virginia Institute of Marine Science
A. C. Schmitzer, Virginia Institute of Marine Science

Abstract

The reproductive cycle of the sea scallop, Placopecten magellanicus in the mid-Atlantic region was studied over a 15 month period. One to 15 samples a month were collected from commercial vessels fishing from Long Island to Cape Hatteras in water depths of 37-68 m. Gonad weights were determined for 4 shell size intervals as an indicator of the reproductive cycle. A sharp decline in mean gonad weights between April-May 1987 and a subsequent increase and decrease in weights between September-November 1987 indicated reproductive processes were occurring on a semiannual cycle. A major spring spawning season was reconfirmed in 1988 by a rapid increase in mean gonad weights between December 1987-January 1988, followed by variable declines in the weights through June. The occurrence of spawning activity for 2 consecutive spring seasons in addition to a fall spawning season suggests that a semiannual reproductive cycle may be a characteristic feature of P. magellanicus in the mid-Atlantic region. The ramifications of spring spawning to the mid-Atlantic sea scallop fishery and management policies are addressed.