158 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



numerous. These ponds produce a much larger quantity of small 

 crustaceans, which are the favorite food of young carp. If the ponds 

 lie dry for some time, a largo numher of injurious insects and other ani- 

 mals which eat roe and young fish are destroj^ed. 



In an area of about IS acres, one hundred thousand young fish are 

 placed. After about four weeks they are again placed in suitable ponds, 

 each 3 acres receiving about five hundred and twenty-five fish, and when 

 late in autumn the young fish are caught for the third time, about 70 

 or 72 per cent of them are left, weighing one-quarter of a pound and 

 more apiece. If at the first transfer only from one hundred and fifty 

 to two hundred and fifty carp per tiJnde are placed in the water (as is 

 done in Austrian Silesia), the carp will weigh about a pound apiece at 

 the end of the first summer. 



At Gustafsberg the young carp (one year old) have of late years been 

 transferred once during the summer, namely, in July. All the ponds 

 have ditches or furrows, which meet in a large hole inside the dike, near 

 its lower part, so that the fish may congregate there and can easil}' be 

 caught when the water is let off. From 75 to 95 per cent of the trans- 

 ferred fish could be caught in autumn, if care was taken to protect tbe 

 fish against their enemies. In 1882 Mr. Wendt set out two hundred 

 and fifty one year's fish per 3 acres. In the autumn of the second year 

 these fish had an average weight of nearly a i)ound, while some weighed 

 li pounds apiece; of fish that were a year older he set out one hundred, 

 and of those that were still a year older (which were in their fourth 

 summer), he put out from forty-eight to seventy-five in an area of 3 

 acres. It takes, however, the experience of many years to decide how 

 many fish of the diflerent ages must be placed in ponds of a certain 

 character and size. Above everything else regard must be liad to tbe 

 nature of the bottom and the water. A barren bottom, where plants 

 and small animals cannot live, is just as little adapted to a carp pond 

 as cold spring-water. As a general rule several small ponds can sui)- 

 port more fish than one large pond of the same extent, for in the smaller 

 l)onds the fisli get a larger amount of shallow and warmer water. For- 

 merly several times more fish were placed in the ponds than is done 

 now. The result as regards weight was the same ; but the economical 

 advantage was less than now, because a small inimber of large fish 

 will fetch a higher price than several small fish having the same com- 

 bined weight. 



Under the conditions referred to fibove, the fish in ]Mr. AVendt's ponds 

 reach a weight of 2A to 4 pounds during the fourth autumn, some fish 

 occasionally reaching a weight of 5 or G pounds. In a less favorable 

 year when many car[) of the above-mentioned age have not reached a 

 weight of 2.} pounds, they are set out in the ponds anew, so as to have 

 another summer lor growing. As a general rule, however, the fourth 

 year is the one during which the Gustafsberg carp become salable. In 

 Prussian Silesia carp reach a weight of 2 to 4 pounds when two and one- 



