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Chapter 6 - Diadromous Fishbetween ages 3 and 6, usually age 5 (Collette and Klein-MacPhee 2002).Hickory shad (Alosa mediocris)Hickory shad occur along the Atlantic coast from theBay of Fundy, Canada to the Saint John’s River, Florida(Levinton and Waldman 2006), but spawning is reportedin rivers from Maryland to Florida (Harris et al.2007). Adult hickory shad appear to spawn in a diversityof physical habitats ranging from backwaters and sloughs,to tributaries, to mainstem portions of large rivers intidal and non-tidal freshwater areas (AMSFC 1999). InChesapeake Bay, hickory shad spawning runs usually precedeAmerican shad runs, typically beginning in Marchand April. Repeat spawning in hickory shad appears to becommon, but tends to vary among river systems. Spawninghickory shad females (ages 3 and 4) broadcast a largequantity of eggs into the water column which are fertilizedby males (ages 2 and 3). After spawning, adults return tothe sea, but their distribution and movements in the oceanare essentially unknown. It is believed that they are highlymigratory and follow a pattern similar to the coastal migrationsof American shad, moving northward from theMid-Atlantic and southeast after spawning. Hickory shadare predators, consuming small fishes, crabs, and squid.Rainbow smelt (Osmerus mordax)Smelt occur on the Atlantic coast from Labrador toNew Jersey, but are most abundant from the southernCanadian Maritime Provinces to Maine. Their range,which formerly extended to the Delaware River, appearsto be contracting northward; state status ranks vary fromSH or “possibly extirpated” in Pennsylvania; to S1 inConnecticut and Rhode Island; to S3 in Massachusettsand S4-S5 northward (Natureserve 2008). Coastal smeltstocks throughout New England declined markedly by the20th century, due to the construction of dams and reductionin water quality. Two concerns identified for manyrivers in Massachusetts Bay are structural impedimentsto spawning habitat and chronic degradation of spawninghabitat from stormwater inputs (Chase and Childs 2001).Smelt are a pelagic, schooling species that spends most ofits time in shallow nearshore waters and may make oceanmigrations, but little is known about this part of its lifehistory. Their movement patterns are associated with seasonalchanges in water temperatures. In summer, schoolsmove to deeper, cooler, waters; in the fall they enter baysand estuaries where they actively feed until the onset ofwinter. Most spawning occurs in fast flowing, turbulentwater in stream sections dominated by rocks, boulders,and aquatic vegetation, about the time ice breaks up in latewinter. After hatching, larvae move passively downstreamin freshwater currents until reaching estuarine waters(Collette and Klein-MacPhee 2002). By mid-summer,juveniles reside in the deeper waters of estuaries, particularlyduring daylight hours. Larvae and juveniles feed uponzooplankton, particularly microscopic crustaceans. Adultsmelt feed primarily on small crustaceans and fish. Smeltin turn are an important prey for a variety of predatoryfish, including, striped bass and bluefish, and several birdand marine mammal species.Sea-run brook trout (Salvelinus fontinalis)Brook trout are native to eastern North America fromLabrador southward to Georgia along the Appalachianchain (Natureserve 2008). Like many other salmonids,including brown trout and rainbow trout introduced tothe East Coast as sport fish, brook trout life histories arehighly variable. Brook trout once exhibited anadromousbehavior in many streams of eastern Canada southwardto Long Island, but few sea run populations remain andmost continue to decline (Doucet et al. 1999). Historicalaccounts suggest that sea-run brook trout were commonprior to the 1700s, and that they suffered the same fate asother anadromous fish when subjected to damming andpollution of rivers. They are now documented in a handfulof sites in Massachusetts, Maine, and maritime Canadabut may still persist as far south as Long Island.6-30Northwest Atlantic Marine Ecoregional Assessment • Phase 1 Report