FISHES OF CHESAPEAKE BAY 
103 
Color of back dark green to bluish; sides brassy; a round, black, humeral spot present (except 
in the young of less than about 70 millimeters in length) and with or without a variable number of 
smaller dark spots on sides behind it; fins mostly pale yellow, some of them often more or less punctu- 
late with dusky. 
Many specimens of this species, ranging from larvae 20 millimeters to adults 370 millimeters in 
length, were examined, and a large series was measured for the purpose of determining the range of 
variation within the species. The menhaden is so well known to those who live on the seashore 
within the range of the species that it is recognized at sight by old and young. The chief recognition 
marks of the species are the rather deep body, the compressed abdomen, deep cheeks, broad opercles, 
deeply emarginate upper jaw, strongly pectinate scales with posterior margins nearly vertical, and 
the greenish and brassy coloration. A pronounced variation in the depth of the body takes place 
within the species, which appears to be correlated, to a large degree, with the state of nourishment of 
the individual fish, the well-nourished fish being deeper than the poorer specimens. Similarly, a 
great variation in the width of the back also exists. When the fish is in a well-nourished state the 
back is very broad and layers of fat lie underneath the skin. The common name “fatback” is very 
appropriately applied to fish in this condition. A large crustacean parasite ( Cymothoa prxgustator ) 
is commonly found inside the mouth of menhaden, giving rise to the name “bugfish.” 
The sexes are not distinguishable externally, so far as known to the writers, and the size attained 
appears to be nearly equal. 
The menhaden feeds on small organisms, which it strains from the water by means of its long, 
slender, and very numerous gill rakers. The feeding and movements of schools of fish, as observed 
in the Patuxent River from aboard the Fish Hawk by the junior author, are described as follows 
in his field notes: 
The fish swam swiftly in circles, like the dust driven by a whirlwind; then suddenly formed in a straight line, continually 
rising and falling at various depths. Each time they rose their mouths were wide open, but it was not possible to see whether or 
not their mouths were open when they swam downward. The fish near the shore seldom “broke water,” but those observed in 
the open swam in compact schools, causing ripples at the surface; at times hundreds of them swiftly darted a few inches out of the 
water, causing a noise that could be heard easily at a distance of 300 feet. One large school was seen to divide into two parts. Some 
schools swam against the tide and then suddenly turned back with the tide. No general direction seemed to be maintained. 
Doctor Linton examined the contents of the alimentary canal of 44 specimens taken in Chesa- 
peake Bay and found that in most cases they consisted of sandy mud, vegetable debris (mostly 
algfe), and some diatoms, and in a few cases they consisted principally of copepods. He gives 
(from his notes as follows) the contents of the alimentary canal of a specimen taken in the lower 
part of the Patapsco River, November 7, 1921, as typical of the lot examined: 
Gizzard full of yellowish mud, which, under high magnification, is resolved, as in previous cases, into vegetable silt with a little 
very fine sand. The vegetable material is reduced to a pulp, but vegetable cells can be distinguished, evidently of algal origin, 
material which makes up the vast majority of the food. Diatoms were present in considerable numbers, but do not constitute a 
large percentage of the food; very small, in fact, much less than l per cent. * * * Intestine filled with the same material. 
Peck (1894, p. 113) gives the food of the menhaden as unicellular organisms, both vegetal 
and animal, together with the smaller Crustacea and other free-swimming forms. 
Concerning the spawning habits of the menhaden, Kuntz and Radcliffe (1918, p. 119) state: 
Observations on the movements of the schools and examination of the reproductive organs lead to the belief that in New 
England spawning takes place in late spring or early summer and that from Chesapeake Bay southward the season is late fall or 
early winter. Some reasons have been advanced for believing that in the Chesapeake region, at least, there are two spawning 
seasons. 
The present writers have secured no information that suggests two spawning periods in Chesa- 
peake Bay during one year. The evidence at hand, however, indicates that spawning takes place 
during the fall, as fish with well-developed (although not ripe) roe were taken only during that 
season of the year. The size and development of the young taken during the winter and spring 
furthermore suggest that they were hatched during the fall. Fourteen larvae caught during January 
had attained an average length of 27.7 millimeters; 6 taken during February averaged 33.5 milli- 
meters; 5 taken during March averaged 27.3 millimeters; 4 taken during April averaged 33 milli- 
meters; and 137 taken during May averaged 46 millimeters. The number of larvae caught from 
January to April, of course, is too small to show the rate of growth during the winter months, but 
at any rate the indications are that it is very slow. These fish all bear large chromatophores, the 
majority of them still possess indications of fin folds, and none of them have developed scales, all 
of which shows that the fish are very young. No larval menhaden were taken during any other 
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