UNITED STATES, FISH-CCLTURE IN THE. 



BOO 



CARP PONDS, WASHINGTON, D. C. 



in deep water, refusing food, in moderately cold coun- 

 tries, from October to April. In the warmer Southern 

 States the period of winter sleep is greatly reduced, 

 and the time of growing increased. Carp do not lose 

 weight in their natural retreats during winter, nor do 

 they grow. The spawning-season begins when warm 

 spring weather has fairly set in, and continues into 

 July, or later. The number of eggs averages about 

 100,000 for each pound of the weight of the fish. The 

 scale-carp is somewhat more prolific than the other 

 two varieties. The favorite spawning -places are spots 

 overgrown with such aquatic plants as the bladder- 

 worts ( Utricularia)* water-plantain (Alisma), water- 

 milfoil (Myriophyllum), pond-weed (Potamogeton), 

 and some members of the water-lily family. The 

 eggs are adhesive. The period of incubation depends 

 mainly upon temperature ; in the colder portions of 

 New England it may be sixteen days, while in Georgia 

 it has been reduced to as little as forty-eight hours, 

 with a temperature of 90 or more. 



The rate of growth of the carp depends upon the 

 average temperature of the water, the nature of the 

 bottom of the pond or river, the amount of food, and 

 the extent of water area. According to Rudolph Hes- 

 sel, a carp-culturist of wide experience, who has charge 

 of the ponds of the United States Fish Commission, 

 the average normal weight of a three-year-old carp of 

 any of the three varieties is three pounds. This aver- 

 age may be greatly increased or diminished through 

 variations of the conditions above mentioned. The 

 carp may be reared in brackish waters, as well as in 

 rivers, lakes, and ponds. 



_ In establishing ponds it is desirable to have a suffi- 

 cient supply of brook or river water at all seasons. 

 The bottom of the pond should consist of clayey loam 

 intermingled with some marl or vegetable mold. But 

 there must not be too much humus or dissolved peat. 

 Surface drainage from fertile fields is advantageous in 

 carp-ponds. Artificial ponds are most readily^ con- 

 structed in a low, undulating region which is without 

 great elevations, and where reservoirs may be cheaply 

 lormed by closing up the small valleys by dams. The 

 depth of the pond need not exceed three feet in the 

 center, and from the margin to a distance of 70 or 100 

 feet it should not be more than one foot. The area 

 intended for breeding must be still shallower, not ex- 



ceeding a few inches in depth. Near the center of the 

 pond a deep cavity, fulty two feet lower than the rest 

 of the bottom, and varying in size according to the 

 area of the pond, must be dug, to serve as a retreat 

 from excessive heat and cold. The pond must be so 

 made that it can be perfectly drained. Near the out- 

 flow end must be provided another excavation, about 

 one foot deeper than the rest of the pond, to receive 

 the fish when the water is drawn off through the out- 

 let-pipe ; this cavity is called a "collector." The 

 drainage is effected by means of a main ditch leading 

 into the "collector," and having intersecting ditches 

 from all parts of the pond. The " collector" ought 

 to have a plank flooring, and must be kept free from 

 mud. The inflow of water into the pond from a 

 stream should be lateral and never direct. Both the 

 inlet and the outlet of the pond must be supplied 

 with series of screens, to prevent the escape of the 

 carp and the intrusion of other fishes. All wood-work 

 exposed to the action of the air : or the water, or both, 

 should be well protected by paint or some other pre- 

 servative. If the pond receives a considerable supply 

 of surface-water, or is liable to overflow in rainy 

 weather, an "overflow" must be provided at the 

 side, and this must be protected by wire-cloth screens. 

 Knolls and islands must be entirely removed from the 

 pond, or they will serve as lodging-places for numer- 

 ous enemies of the fish. In stocking ponds, three fe- 

 males and two males, or sometimes twice as many of 

 each sex, are allowed to one acre of water. Mr. Hes- 

 sel recommends that small ponds be surrounded by a 

 tight board fence, three to four feet hi^h, and imbed- 

 ded in the ground from four to six inches. This will 

 keep out the snapping-turtle, the most voracious and 

 dangerous enemy of the carp. Aquatic birds, otters, 

 musK-rats, minks, frogs, water-snakes, and a host or 

 other animals, in the water and out of it, prey Upon 

 fish and are especially destructive to carp. Carp must 

 be kept entirely apart from other fishes, and they 

 must be protected from the enemies above mentioned. 

 Facility in draining the pond will insure the extermi- 

 nation of foes within, and the outride foes must be 

 killed by shooting and trapping. Regular carp-cult- 

 ure requires a hatching-pond, a breeding-pond, and a 

 culture-pond. The hatching-pond need not be as 

 large as the breeding-pond, ana its depth should not 



