62 FISHES OF PENNSYLVANIA. 

The shad reaches a length of two feet. It is claimed that fifty years 
ago shad weighing from eight to thirteen pounds were not uncommon 
in the Susquehanna. It is stated that even larger individuals were 
taken. In California the shad reaches a larger size than it does in the 
East; specimens weighing from thirteen to fourteen pounds being 
often seen in the markets. The average weight of females is four or 
five pounds. The male is much smaller. 
The young shad remain in the rivers until the approach of cold 
weather, when they descend to the sea and are usually seen no more 
until they return as mature fish ready for reproduction. They are known 
to feed upon small flies, crustaceans and insect larve. They have been 
fed with fresh water copepods and kept alive in this way until they had 
obtained a length of more than one inch. In the carp ponds, at Wash- 
ington, Dr. Hessel succeded in rearing shad upon the Daphnia and Cy- 
clops to a length of three or four inches, and one time when they had 
access surreptitiously to an abundant supply of young carp, well fed in- 
dividuals reached a length of sixinches by the first of November. Shad 
have been kept at the Central Station of the United States Fish Com- 
mission over the winter, but at the age of one year, doubtless for lack 
of sufficient food, the largest was less than four inches long. At this 
age they were seen to capture smaller shad of the season of 1891, which 
were an inch or more in length. The Commissioner of Fisheries de- 
tected young shad also in the act of eating young California salmon, and 
upon one occasion found an undigested minnow, two or three inches 
long, in the stomach of a large shad; adults have been caught with 
minnows for bait. The principal growth of the shad takes place at sea 
and when the species enters the fresh waters for the purpose of spawning 
it ceases to feed, but will sometimes take the artificial fly and live min- 
nows. 
The migratory habit of the shad has already been referred to. The 
spawning habits have been thus described by Marshall McDonald: ‘The 
favorite spawning grounds are on sandy flats, bordering streams and on 
sand bars. The fish appear to associate in pairs, usually between sun- 
down and eleven p.m. When in the act of spawning they swim close 
together near the surface, their dorsal fins projecting above the water 
and their movements producing a sound which fishermen cail ‘washing.’ 
The eggs are expressed by the female while in rapid motion; the male fol- 
lowing close and ejecting his milt at the same time. Such of the eggs 
as come in contact with the milt are impregnated, but the greater portion 
of them are carried away by the current or destroyed by spawn-eating 
fishes. After impregnation the eggs sink to the bottom and, under favor- 
able conditions, develop in from three to eightdays.” According toSeth 
Green, the embryo shad swim as soon they break the shell and make 
their way to the middle of the stream where they are comparatively safe 
from the predaceous fishes. A mature female shad of four or five 
