Retention of larval haddock Melanogrammus aeglefinus in the Georges Bank region, a gyre-influenced spawning area

Abstract

Monthly distribution patterns of haddock larvae are described from coastal Marine Resources Monitoring, Assessment and Prediction surveys as part of a broad-based program to study recruitment processes in shelf waters from Cape Hatteras, North Carolina [USA] to Cape Sable, Nova Scotia [Canada], an area of .apprx. 260,000 km2. Within this area haddock spawn during winter and spring. Peak spawning occurs in late March-early April. The principal spawning grounds lie over the eastern half of Georges Bank. Other spawning areas include Nantucket Shoals, western Georges Bank, coastal waters of the Gulf of Maine, and the western perimeter of the Scotian Shelf. A large anticyclonic gyre and strong rotary tidal currents hold haddock larvae on Georges Bank. The gyre carries haddock larvae westward along the southern half of the bank, largely over depths between 50 and 100 m. Some are advected as far west as Nantucket Shoals but most are retained on the bank east of Great South Channel. There is no evidence of a significant loss of haddock larvae south across the shelf break nor do larvae originating on Georges Bank mix with their counterparts in the Gulf of Maine or along the western part of the Scotian Shelf.