ARTIFICIAL PROPAGATION" OF SHAD 485 



introduction of additional half-pints of water. When the scale is 

 being constructed, the central glass tube is stopped at the lower 

 end, that it may displace an amount of water equal to the amount 

 of eggs it will displace in practice. Each line on the measuring stick 

 registers 7,000 shad eggs. The number of eggs in a liquid pint is 

 established by actual count. 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 semibuoyant eggs die, under proper conditions, after hatching 

 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. 



FEEDING AND REARING 



The young shad swims vigorously, by rapid and continuous vibra- 

 tion of the tail, from the moment it loaves the egg. It is colorless, 

 transparent, and gelatinous. Several hundred in a dipper are scarcely 

 discernible. It has a relatively large yolk sac, but supports it with 

 ease during the first 4 or 5 days after hatching, the small quantity 

 remaining after this time not being visible externally, althougn found 

 in shad fry 14 to 16 days old. Minute conical teeth make their 

 appearance on the lower jaws and in the pharynx about the second 

 or third day after hatching. The jaws at 3 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 10 or 12 days after the young fish had left the egg. At 

 about the middle of the second week considerable may be seen, but 

 the intestine is then not often very densely packed. At the age of 3 

 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 

 young shad follow them, and in aquaria they take Ci'ustacea freely. 

 In salt-water aquaria they may bo fed upon chopped oysters and 

 canned herring roe. 



Experiments with young shad were earned 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 5 months 

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

 \\'as added to from day to day for nearly a week, when it was brought 

 up to 1.018, or the same specific gra\ity as that of the water used in 

 the marine aquaria. At the time that these were placed in the 

 brackish water othei-s were put into fresh-wat-er a{[uaria, but the 

 latter died within 3 days. Those in salt water began in 2 or 3 days 

 to take food, consisting of choj)ped oysters, clams, and beef, the pref- 

 erence being for oysters. At first they would take food only when 

 it was sinking, later they began taking it oft' plants where it had 

 lodged, and finally from the bottom. Nearly all remained healthy, 

 plump, and active for 6 months, some living until about midsummer. 



For a number of years two or three million shad fry were reared 

 annually at the fishponds, Washington, D. C. A 6-acre pond was 



