Appendix 3, continued. Species life history notes 



this report are assumed to be at least partially sus- 

 tained by stocking. 



• Haddock: Melanogrammus aeglefinus rarely enter 

 salinities <30 ppt and generally avoid depths of < 9m. 

 Juvenile haddock remain pelagic for several months 

 before settling to the bottom. At present stocks are 

 believed to be severely depleted compared to historic 

 levels (NEFSC 1992). 



• Silver hake: Merluccius bilinearis is also known as 

 whiting. Migration is extensive, with overwintering in 

 deeper waters of the Gulf of Maine and movement to 

 shallow water in the spring to spawn. This report 

 focuses upon the northern stock, although there is a 

 southern stock south of Georges Bank which appears 

 to have different seasonal migration patterns (NEFSC 

 1992). 



• Atlantic tomcod: Microgadus tomcod\s also known 

 as frostfish. This semi-anadromous species spawns in 

 fresh and brackish water, but the larvae can only 

 develop in brackish water. Therefore, they drift sea- 

 ward shortly after hatching so that larvae, and young of 

 theyear, are found primarily in the mixing zone (Stewart 

 and Auster 1987). 



• Red and white hakes: The early life stages of 

 Urophycis chuss and U. tenuis are often not distin- 

 guished from each other in ichthyoplankton surveys. In 

 the Gulf of Maine, adult U. chuss are more abundant 

 than juveniles, whereas the reverse is true for U. 

 tenuis. North of Cape Cod, U. tenuis appears to be the 

 more abundant species. Depth distribution of both 

 species varies by age and season, with younger juve- 

 niles tending to be in shallower areas (Musick 1974, 

 Markleetal. 1982). Red hake juveniles often live within 

 or around sea scallops (Placopecten magellanicus). In 

 the North Atlantic, spawning of white hake has been 

 variously described in the winter and spring, 

 aperiodically throughout the year, and/or in the sum- 

 mer (Bigelow and Schroeder 1 953, Markle et al. 1 982). 

 Clearly, the reproductive period is not well defined for 

 estuaries in the Gulf of Maine and this is reflected in our 

 assessment. 



• Mummichog The entire life cycle of Fundulus 

 heteroclitus is completed within the estuary, and all life 

 stages are euryhaline. One of the most abundant 

 fishes in East Coast estuarine marsh habitats, F. 

 heteroclitis often co-occurs in the North Atlantic with 

 the less abundant F. majalis, particularly south of 

 Massachusetts Bay. F. heteroclitis is relatively inactive 

 and may move to deeper water in the winter months, 

 but it is expected to be resident year-round in estuaries. 

 Mummichogs may spawn more than 8 times in a 

 season. The eggs incubate in air and are not sub- 



• Atlantic menhaden: Brevoortia tyrannus are also 

 known as pogies, and are summer migrants to the 

 North Atlantic region. Spawning generally occurs off- 

 shore and south of Cape Cod (Rogers and VanDen 

 Avyle 1989), where larvae and juveniles move inshore 

 and into estuaries. Juveniles are often highly abundant 

 in estuarine waters south of Cape Cod. The spawning 

 status north of Cape Cod is unclear, but it is assumed 

 that primarily large adults move into the North Atlantic 

 to feed. There is high intra- and interannual variability 

 in the presence and abundance of this species, espe- 

 cially in northern areas. 



• Atlantic herring: Clupea harengus migrate from 

 feeding grounds along the Maine coast during fall, 

 arriving in southern New England during winter (Kelly 

 and Moring 1986). Larger individuals move further 

 distances. Spawning begins earliest (late summer to 

 early fall) in northern locations and progressively later 

 westward and southward. Spawning occurs just out- 

 side the mouths of many North Atlantic estuaries/ 

 embayments (e.g., Massachusetts Bay, Saco Bay, 

 Boothbay Harbor, Blue Hill Bay, Machias Bay) where 

 demersal eggs are typically deposited on rocky or 

 gravelly substrates. Larvae are dispersed to the estu- 

 aries/embayments upon hatching. Significant mortality 

 occurs during this stage, presumably from predation 

 and food limitation (Campbell and Graham 1991). 

 Larvae become juveniles, called "brit herring," in the 

 spring and form large schools inshore. During summer, 

 the larger juveniles are harvested in a directed fishery 

 as "sardines." Adults are also commercially harvested. 

 The possibility of northern and southern breeding 

 stocks within the Gulf of Maine is presently under 

 investigation. 



• Atlantic salmon: Salmo sa/arisanadromous. Spawn- 

 ing adults (S) occur in freshwater during the fall. Eggs 

 (E) overwinter in a gravel nest, called a "redd," until they 

 hatch in the spring as yolk-sac larvae (L), called "alevins." 

 After yolk-sac absorption, the "fry" disperse from the 

 redd. Juveniles (J), called "parr," remain in freshwater 

 for 2-3 years and then mature into "smolts" which 

 migrate to the sea. Some adults, called "grilse," spend 

 one year feeding at sea before returning to their natal 

 river to spawn. Other adults return after two or more 

 winters at sea and are usually larger than grilse. 

 Repeat spawners have also been recorded but are 

 relatively uncommon in the North Atlantic (Danie et al. 

 1 984, Friedland 1993). Salmon are stocked as fry, parr, 

 and/or smolts in several rivers throughout the Gulf of 

 Maine to attempt restoration of populations. The abun- 

 dance of salmon in the North Atlantic region at present 

 is extremely low. Although there have been docu- 

 mented returns of wild salmon — most notably in the 

 Penobscot, Narraguagus, and Merrimack rivers (Anony- 

 mous 1993) — most of the populations mentioned in 



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