XLVIII REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



cessfully reared on the supply of natural food. The pond in which 

 youug shad were reared was prepared by planting vegetation favorable 

 to the growth of small Crustacea such as Daphnia, Cypris, and Cyclops, 

 upon which the young shad feed. The plants- introduced were Potam- 

 ogeton, Natans, Gramineus, Crispus pectinatus, and also bushy Myrio- 

 phyllum of different varieties. 



A Nelumbmm, which was growing in the pond intended for shad, was 

 found to be unfavorable to the experiment and it was removed. Vallis- 

 neria and Polygonum amphibium were added to the plants in the pond. 



Shad fry were introduced April 26, 28, and 30 ; May 1, 2, 3, 4, and 

 6. On May 3 the fry were seen in water 3 to 4 inches deep, on sandy 

 bottom, feeding upon minute Crustacea. From May 3 to May 7, a raw 

 north wind drove the aniinalculae into deeper water, where the shad 

 followed them and were lost from sight. Dr. Hessel began measuring 

 the fish May 20, continuing at intervals of from five to fifteen days 

 until October 10. The growth of the shad diminished towards the 

 middle of August. The Cyclops, Cypris, etc., although very abundant 

 in the pond, were too small to satisfy their appetite and the larger 

 Gammarus pulex was not present. In order to determine whether or 

 not the young shad would eat the fry of other fish, Dr. Hessel made 

 the following experiment: 



At those points of the pond mostly frequented by shad I placed, about June 20, 

 from 80 to 100 carp, ten days old. The young shad were then about 3 centimetres 

 long, and the carp about 6 millimetres (or one-fourth of an inch). 



The shad at once attacked the carp, and ate them up. I can not say that it is the 

 nature of the shad to eat other fish; but in this case it may have been the want of 

 Crustacea of proper size which compelled them to eat the carp fry, and it does not 

 necessarily follow that they do so in open waters of rivers and the ocean. I am sat- 

 isfied, however, that they do this in inclosed waters, from the following fact : 



In 1886 a few cans of shad fry from the U. S. Fish Commission wore deposited in 

 the same point, in order to test the practicability of raising shad in the pond. The 

 shad grew rapidly. In May the carp in the pond spawned and after the eggs were 

 hatched an abundant supply of young carp was observed. The carp fry gradually 

 disappeared and when the pond was drawu off, instead of 120,000 young carp which 

 were expected, only 25,000 were taken out. At the same time, we found about 

 12,000 young shad (3 or 7 inches in length, which was three or four times the average 

 size of the shad raised this year. 



They accomplished this abnormal growth at the expense of the young carp which 

 they had devoured. 



October 27, 1887, about 800,000 young, of 2J to 3 inches, were libe- 

 rated and entered the Potomac. 



This method is capable of general application as a means of stocking 

 our rivers. I Would select low meadows along the tidal portions of 

 streams, which are bare at low water; by dikes I would exclude the 

 tide water and allow the ponds to fill by seepage or surface drainage. 



Ponds of several hundred acres area may be constructed at moderate 

 expense. Each season I would stock these ponds with fry, and in the 

 fall open the sluice gates and let the shad pass out into the rivers. Pur- 



