FISHES OF CHESAPEAKE BAY 
95 
young shad may be separated by the much narrower and proportionately deeper cheek and by 
the much lower and broader angle near the middle of the sides of the upper margin of the mandible. 
The young shad does not differ greatly from the adult, except that the body is more slender, the 
gill rakers much fewer, and the dark spot at the shoulder is undeveloped. The sexes are very 
similar, except that the female reaches a larger size than the male. 
The young shad, according to published accounts, feed on small crustaceans, insects, and 
insect larvae, as well as on small fish. This statement was verified through the examination of 
14 stomachs. Stomachs of specimens ranging from to 2 % inches in length, taken in fresh 
water, had fed mainly on adult insects but also on ostracods. Specimens somewhat larger, ranging 
from 4 to 6 inches in length, taken in salt or brackish water, had fed almost wholly on small crus- 
taceans (Mysis), but one stomach contained a small amount of plant tissue and another contained 
fragments of a small fish. 
Little or no food has been found in the shad while they were migrating up rivers. Various inves- 
tigators, however, have examined the stomachs of adult fish caught in the sea or at the mouths 
of estuaries and have found food. An adult female taken in the southern part of Chesapeake Bay 
early in December, 1921, and examined by us, had the stomach gorged with parts of plants, con- 
sisting not only of the softer parts but also of hard stems. Fragments of a molluscan shell also 
were present. Perley (1851, p. 139) found that the shad in the Bay of Fundy fed on shrimp and 
“shad worm.” Mordecai (1860, p. 278) examined shad stomachs from the vicinity of Savannah, 
Ga., and as a result states that “shad feed and 
fatten on marine fuci and microscopic organisms 
that are parasitically attached.” Leidy (1862, p. 
2) obtained a shad in a market and upon opening 
it found in its stomach nine small fish, which were 
identified as follows: Three Hydrargyra swampina; 
five Pcecilia latipinnis, and one Cyprinodon ovinus. 
As these species inhabit fresh or slightly brackish 
water, and as the shad was probably received in 
Philadelphia, it is likely that it was caught in Del- 
aware Bay. Leidy (1868, p. 228) examined a shad 
caught in the fall, probably off the coast of New 
Jersey or in Delaware Bay, and found in its stom- 
ach 30 sand launces ( Ammodytes americanus) , 2 to 
4 inches long. Baird (1874, p. LVIII) says that 
in the sea the food of the shad consists “of worms, 
small fishes, and most largely of minute crustaceans, especially of the genus Mysis.” Huyler 
(1876, p. 233) examined the stomachs of 15 shad caught in the North River near Fort Lee, N. J., 
on May 5, 1874, and found them containing many young shrimp about half an inch long. One 
of these stomachs contained several hundred shrimp. Prime (1876, p. 138) reports the capture 
of several shad (at least one with full roe) with artificial flies in the Connecticut River, thus indi- 
cating that at times the shad will feed just prior to spawning. It is of interest to note that these 
fish were caught on July 1, at the very end of the spawning season for that region. Smith (1896, 
p. 405) quotes Seth Green as saying that sand fleas [Gammarus?] are the principal food of the old 
shad in the Atlantic. Bean (1903, p. 207) says that the shad coming in to spawn will sometimes 
take the artificial fly and live minnows. Willey (1923, p. 313) examined many shad from the 
Nova Scotian coast of the Bay of Fundy and found the stomachs to contain chiefly copepods (Acartia, 
Temora, and other genera), mysid shrimp, and the larval stages of barnacles. Leim (1924) exam- 
ined the stomachs of about 350 shad caught in Scotsman Bay, Bay of Fundy, during 1920 and 1922, 
consisting of mature and immature fish. Copepods formed the chief food for the smaller shad, 
but were of lesser importance in the diet of fish longer than 40 centimeters (16 inches). Mysids, 
however, while eaten sparingly by the younger fish, formed the chief constituent of the food of the 
adult shad. Copepods and mysids together formed about 90 per cent of the food of the shad of 
all sizes. Among the foods of lesser importance were ostracods, amphipods, isopods, decapod larvae, 
insects, mollusks, algae, fish eggs, and fish. Bigelow and Welsh (1925, p. 117) found adult shad 
taken in the Gulf of Maine in summer packed full of copepods (chiefly Calanus). 
Fig. 54 . — Alosa sapidissima. Note narrow, deep cheek bone 
and rather long, slender mandible without a pronounced 
angle on its upper margin 
49826—28 7 
