Fishes of the Western North Atlantic 303 



in salt water, except during the migration to and from tlie spawning grounds. There- 

 fore it is of interest that an adult female, caught in Chesapeake Bay in December, 

 was gorged with parts of plants, among which were fragments of a mollusk shell. It 

 has been reported also that adults taken in the vicinity of Savannah, Georgia, had fed 

 on plants. Others caught near Fort Lee, New Jersey, had fed liberally on young shrimp, 

 and still others, taken in Delaware Bay, had eaten small fish. 



From an examination of about 350 stomachs of both mature and immature fish 

 caught in the salt water of Scotsman Bay, Bay of Fundy, Leim found that, while cope- 

 pods constituted the chief food of the smaller ones, as in fresh water, these crustaceans 

 were unimportant in fish 400 mm and more in length (^J: 68). Mysids, which were 

 sparingly eaten by small fish, were the chief food of adult fish. In general, about 90 "/o 

 of the specimens of all sizes from that area had eaten copepods and mysids, with 

 ostracods, amphipods, isopods, decapod larvae, insects, mollusks, algae, fish eggs, and 

 fish making up the remainder. After examining many stomachs of specimens taken in 

 the Bay of Fundy, Willey also concluded that the chief foods consisted of copepods and 

 mysids, to which he added shrimp and larval stages of barnacles (JJJ: 313-320). 

 Stomachs of fish from the Gulf of Maine have been found full of copepods (chiefly 

 Calanus). American Shad also feed greedily on pelagic euphausiid shrimps. 



Enemies. No doubt the larger predatory fishes are the principal enemies of the 

 young while the latter are in the rivers. Although no records at hand show definitely 

 that this is so, it can scarcely be otherwise, for the young are not rapid swimmers and do 

 not ordinarily seek protection among plants or other cover. Furthermore, they are small 

 enough, at least during the early part of summer, to be swallowed by bass and other 

 carnivorous fishes only an inch or two long. Water birds, turtles, and water snakes 

 no doubt feed on them too. The toll taken by predatory fishes while the young are en 

 route to the sea may not be very great, for this migration takes place in the fall when 

 many marine fishes (at least in Chesapeake Bay) have left the shallow waters. At sea 

 they doubtless fall prey to all the larger predaceous fishes, and perhaps to finback whales 

 as well. 



The chief enemy of the adults is man, who has not only depleted the stock in many 

 rivers through overfishing but has cut them off from spawning areas through the 

 construction of barriers and by polluting the waters with deleterious wastes. 



Parasites. The parasites of yf. sapidissima have been made known principally through 

 several papers by Edwin Linton and by Charles B. Wilson, based mostly on specimens 

 obtained from fish caught in the vicinity of Woods Hole, Massachusetts. The findings 

 were summarized by Sumner, et al. {123: 742) as follows: "Acanthocephala (Linton) 

 Echinorhynchus acus. Nematodes (Linton) — Ascaris adunca, Ascaris sp. (immature). 

 Copepods (C. B. Wilson) — Caligus rapax." To this list was added the copepod Ler- 

 naeenicus radiatus (135: 59). Working with both young and adults from the Shuben- 

 acadie River and Scotsman Bay, Leim found no external parasites and only three 

 internal ones, namely "distomes, nematodes, and Acanthocephali" (^J : 74). It is not 

 stated whether any of these parasites were considered seriously detrimental to the host. 



