154 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



practice. Eacli line on tlie measuring- stick registers 7,000 shad eggs. 

 The number of eggs in a liquid pint is established by actual count. 

 Those which are very young or have been lately on trays are not of 

 normal size and not qualified for measurement. The eggs are at rest 

 when measured. 



The jar contents are determined by placing the short leg of the 

 measuring-stick over the top, with the other pointing downward and 

 touching the side of the jar. The number is indicated on the scale at 

 the point opposite the surface of the bulk of the eggs. Scarcely any 

 semi-buoyant eggs die, under proper conditions, after hatching out has 

 commenced, and a close approximation to the number of fry may be 

 obtained from the last measurement, which is 

 made after the careful removal of all dead eggs 

 and the bursting forth of the first young. 



FEEDINa AND REARING. 



The young shad swims vigorously, by rapid 

 and continuous vibration of the tail, from the 

 moment it leaves the egg. It is colorless, trans- 

 parent, and gelatinous. Several hundred in a 

 dipper are scarcely discernible. It has a rela- 

 tively large yolk-sac, but supports it with ease 

 during the first four or five days after hatching, 

 the small quantity remaining after this time not 

 being visible externally, although found in shad 

 fry 14 to IG days old. Minute conical teeth make 

 their appearance on the lower jaws and in the 

 l^harynx about the second or third day after 

 hatching. The jaws at three months are armed 

 with teeth slightly curved. 



Young shad feed on other minute organisms, 

 such as exceedingly small crustaceans. Food 

 has never been observed in the alimentary canal 

 until ten or twelve days after the young fish had 

 left the egg. At about the middle of the second 

 Application of a measur- week considerable may be seen, but the intestine 

 iiigscaletoa jarof shad jg then not often Very densely packed. At the 

 ^Sg8- g^gg Qf three weeks an abundance of food is 



found. They have been known at this early age to eat their own kind, 

 and later the young carp and salmon. When cold, raw winds drive 

 the crustaceans into deeper water, the youug shad follow them, and 

 ill aquaria they take Crustacea freely. In salt-water aquaria they may 

 be fed upon chopped oysters and canned herring-roe. 



Experiments with young shad have been carried on for several years 

 at Central Station in salt-water aquaria. On one occasion about 250 

 were received in October, at which time they were about five months 

 old. They were put in brackish water, specific gravity 1.005, which 



