FISHES OF THE GULF OF MAINE 275 



preference for shallow water is reflected in the large numbers caught in pound nets 

 during the years when they visit the Gulf of Maine. Probably few descend deeper 

 than 5 to 6 fathoms during the summer, but the precise level at which they live 

 at any given locality is governed by their food; on open coasts they often feed on 

 bottom in the surf. They are also bottom feeders in certain inclosed waters, e. g., 

 parts of Delaware Bay. 



As Welsh and Breder (1924, p. 158) point out, very little is known regarding 

 the movements of the schools of weakfish during their annual stay on the coast, 

 but it is probable that these depend largely upon the configuration of the coast 

 line. In Delaware and Chesapeake Bays, for example, they describe the main 

 bodies of fish as running far up on their first arrival, then returning seaward to 

 the ocean in June, but reentering the bays in the later summer. However, it is 

 doubtful whether this on and off shore migration, which is associated with spawn- 

 ing, occurs on such open coasts as those of Cape Cod Bay. 



The winter home of the northern weakfish is still to be discovered, but it is 

 now generally assumed that their autumnal migration takes place to avoid falling 

 temperature, and that they either move offshore to pass the cold season on the 

 continental edge, or southward. 



Food. — Weakfish are carnivorous and voracious, feeding on a wide variety of 

 animals, including crabs, amphipods, shrimps, and squid, but chiefly on smaller 

 fish, such as menhaden, butterfish, herring, scup, anchovies, silversides, and mum- 

 michogs, of which they destroy vast quantities. The precise diet varies with the 

 locality (that is, with what is most readily available), but menhaden is probably 

 the most important single item, and adult weakfish usually depend on fish, though 

 occasionally they have been found feeding exclusively on crustaceans, but we can 

 not learn that shellfish have ever been found in weakfish stomachs. The young 

 subsist chiefly on fish fry, shrimp, and on other small crustaceans, larval as well 

 as adult, and the proportion of Crustacea in the diet averages much greater with 

 small weakfish than with large. 36 Weakfish bite very greedily on various kinds of 

 bait, especially on shedder crabs, clams, shrimp, and mummichogs. 



Breeding habits. — Weakfish spawn from May to October on the middle Atlantic 

 coast, with the chief production of eggs between mid-May and mid-June, probably 

 June and July in Massachusetts Bay. The following account of the breeding and 

 development of the weakfish is condensed from Welsh and Breder (1924, p. 150). 

 The eggs have been taken in tow nets at various localities in temperatures ranging 

 from 60° to 70°, in salinities of 28.01 to 30.9 per mille, and it is probable that weak- 

 fish spawn locally around the shores of Cape Cod Bay in years when the fish are 

 plentiful there, as they do regularly about Woods Hole, the summer temperature 

 of the surface being sufficiently high. Spawning is confined to the immediate 

 vicinity of the coast, taking place chiefly in the larger estuaries or close to their 

 mouths, usually at night. The eggs are buoyant, spherical, 0.74 to 1.1 mm. in 

 diameter, usually with one, rarely with as many as four, oil globules that coalesce 

 into one large one as development progresses. Incubation occupies 36 to 40 hours 



"For diet lists of weakfish of various sizes and from many localities! see Welsh and Breder (1924, p. 159), and also Peck (Bulle- 

 tin U. S. Fish Commission, Vol. XV, 1895 (1896), p. 352). 



