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Chapter 7 - Demersal FishShelf. Spawning season for species in this group occursthroughout much of the year. Croaker spawn from July toDecember, with a peak in late fall and early winter. Spotspawning begins in the fall and continues through thewinter into early spring. Tautog spawning primarily occursnear the mouths of estuaries and inshore waters andfollows a northward progression through the summer, beginningin April in the southern part of the Mid-AtlanticBight and extending to the northern area by May. Peakspawning in the central Mid-Atlantic Bight is reported tooccur in June and July and declines by August. Weakfishspawning occurs in nearshore coastal waters after the inshorespring migration from March through September,peaking between April and June.Fertilized eggs of all four species are buoyant and pelagic(ASMFC 2009). Eggs and larvae remain in the watercolumn and are transported to coastal and estuarine watersby tides, currents, and other oceanographic processes.Juveniles utilize a variety of benthic habitats within nearshorenursery areas depending on species before migratingoffshore to the open ocean along the Continental Shelf.These species eat a variety of benthic prey items includingpolychaetes, mollusks, mussels, shrimp, and fishes. Tautogprey heavily on blue mussels, while weakfish are muchmore piscivorous than other species in the group, preyingon a variety of fishes including menhaden, shad, river herring,sea herring, and sand lance. Weakfish are recognizedas an important top predator in Chesapeake Bay, feedingalong the edges of eel grass habitats and along channeledges, rock, and oyster reefs (ASMFC 2009). Specieswithin the group are preyed upon by a variety of fishes,spiny dogfish, skates, sharks, and in the case of juveniletautog, piscivorous seabirds (Steimle et al. 1999c).Offshore Wintering GuildThe fishes included in the offshore wintering are characterizedby similar movements, habitats, and food habits(Musick and Mercer 1977; Colvocoresses and Musick1984). In particular, these species generally move intoshallow coastal waters in the summer months then moveoffshore to the Continental Shelf during winter months asnearshore water temperatures decrease. The offshore winteringguild group includes black sea bass (Centropristis striata),northern sea robin (Prionotus carolinus), scup (Stenotomuschrysops), and summer flounder (fluke, Paralichthys dentatus).Global distribution of these species is limited to the westernAtlantic, from Nova Scotia to Florida. Within theNorthwest Atlantic, highest numbers are found fromNarragansett Bay in Southern New England to CapeHatteras, North Carolina. However, all species occur onportions of Georges Bank and the Great South Channeland in the Gulf of Maine, particularly in and aroundMassachusetts Bay and the Jeffreys Ledge and StellwagenBank area.Species in this guild undertake distinct season migrations,moving inshore and offshore in response to changes inwater temperature. Summer flounder, scup, and black seasbass display strong seasonal movements, occupying shallowcoastal and estuarine waters in the spring and summerand moving offshore onto the Continental Shelf duringthe colder winter months. These annual migrations areapparently triggered when bottom water temperaturesapproach 7 o C (Packer et al. 1999f; Steimle et al. 1999d;Drohan et al. 2007). Northern sea robin found north ofCape Hatteras make similar seasonal migrations, seeminglytriggered by a broader temperature range of 4.5 to15.5 o C (Collette and MacPhee 2002).Species in the offshore wintering guild utilize a varietyof coastal and shelf habitats depending on season. Adultsummer flounder show a strong preference for coarse,sandy substrates in nearshore coastal waters, generallyoccurring at depths less than 25 m (Packer et al. 1999f).Adult scup are found in a variety of benthic habitats inthe warmer months, including soft, sandy bottoms andon or near structures including rocky ledges, wrecks, artificialreefs, and mussel beds, although they appear todemonstrate a strong preference for mixed sand and muddeposits in Long Island Sound. Specific habitats usedby adults during the offshore over-wintering period arepoorly defined (Steimle et al. 1999d). Adult black sea bassare strongly associated with structurally complex habitats,7-80Northwest Atlantic Marine Ecoregional Assessment • Phase 1 Report