BULLETIN OF THE UNITED STATES FISH COMMISSION. 403 



I finished my two spawning ponds, and stocked them immediately. In 

 one of them I placed one spawner and two milters (mirror carp, weigh- 

 ing 7 pounds each). The first pond is about 40 meters long and 7 meters 

 broad (322 square meters = about 3 ares, or T § 7 hectares). The depth 

 of water was 40 centimeters at the place where it flowed in the pond, 

 and 90 centimeters where it flowed out. The second pond is just as 

 large, but is stocked with 04 female carp and 30 milters, each weighing 



I pound (this should probably be 1 kilogram). The carp were placed 

 in the pond on the 4th of June; on the 5th they spawned, and on the 



II th the young carp left the eggs. One of the female fish has produced 

 so many young fish that I hardly know where to place them; and the 

 same is the case in the second pond. The mirror carp resemble the 

 specimen sent with this letter (on an average 4 centimeters long). I 

 have already taken out 8,000 and put them in other ponds; and still 

 the pond is so full that one fish is almost on another; there are proba- 

 bly 300,000 fish, if not more, left in the pond. They seem lively and in 

 good condition, but I fear that many will die in consequence of over- 

 crowding. These young carp, when placed in a pond 1 meter broad 

 and meters long (0 square meters), and 10 centimeters deep, died at 

 the rate of 500 in a day, although I placed fresh water in the pond twice 

 every day, once in the morning and once in the evening. It is also 

 noticed that in the two large ponds (each having an area of 322 square 

 meters) the carp invariable only stay in the places where the water 

 flows into the ponds; they crowd towards the water at its influx in such 

 enormous uumbers that on Monday I caught 2,234 at a single dip of 

 the catcher. Along the edges of the pond the fish gather in very large 

 crowds. I feed them with boiled fish-roe, which I scatter in the water, 

 near the edges, and which the fish devour so eagerly that not a single 

 fish egg is left. Have you ever heard of anything like it ? In the second 

 pond there are perhaps several millions of fish, but they are not as large, 

 only about half the size of those in the first pond." 



These statements regarding two ponds stocked in different ways show 

 clearly that vast numbers of young fry can be raised in small flat ponds 

 where no dangers threaten the eggs and young fish, and where it is possi- 

 ble to keep a strict surveillance; and that more young fry are obtained 

 from one set of spawners and milters than from another. 



The result of the experiment made in the first pond shows more 

 especially that the method to compose a set of more milters than 

 spawners, guarantees the impregnation of all the eggs. To judge 

 from the large number offish hatched in the above-mentioned ponds, it 

 seems that all the eggs of one spawner had been impregnated, and that 

 young fish had been hatched from them. 



It may of course be questioned whether the impregnation was caused 

 by one or both milters. It is, however, doubtful whether, with a pro- 

 portion of one milter to two spawners, all the eggs of each one of the 

 spawners would be impregnated by that one milter. 



