Abstract
Georges Bank is the most productive sea scallop fishing ground in the world, but little is known about the regional spawning patterns. The sea scallop rotational management plan is based on yield projections estimated from shell height/meat weight relationships. Semiannual spawning may influence yield projections, impacting fishery allocations. This study identifies spawning events at two locations on Georges Bank: one in Closed Area I (CAI) and the other in Closed Area II (CAII). We hypothesize that spawning is semiannual, spring spawning is incomplete compared with autumn spawning, and reproductive stage differs temporally between areas. Scallops (n = 1,871) were collected during a monthly dredge survey in these two areas from two sites from March 2011 through June 2013. Tissues from scallops (shell height ∼130 mm) frozen at sea, were oven-dried and the gonosomatic indices (GSIs) were analyzed to identify spawning events. Oocyte diameter was measured to determine maturity. Bottom temperature was recorded. Semiannual spawning occurred in both closed areas. Spawning rates were similar, but autumn spawning was greater in magnitude than spring spawning. The timing of gametogenesis was similar between sites. Bottom temperature patterns suggest different oceanographic conditions between areas. A semiannual sea scallop reproductive cycle on Georges Bank could influence recruitment and growth assumptions affecting future management decisions.