BULLETIN OF THE UNITED STATES FISH COMMISSION. 6 



large enough to swallow such a carp. The carp occasionally, as in the 

 famous carp ponds of Charlottenburg, near Berlin, reaches the age of 

 a hundred and more years. 



It is well known that all fish have a very large number of eggs. As 

 the "first incarnation" of the vertebrate type, the last and highest 

 grade of which is man, their body has such very simple fundamental 

 forms as to enable nature to produce its germs in every female fish in 

 hundreds of thousands of copies. Even in this respect the carp occu- 

 pies, on account of the large number of its eggs, a very prominent place 

 among fish. It nevertheless indulges in the pleasure of spawning only 

 once a year, in spring, when the warm May sun raises the temperature 

 of the ponds to a comfortable condition. Then its " spawning season " 

 commences, and the male and female fish niay be seen, principally dur- 

 ing the early hours of the morning, swimming about in the water at a 

 lively rate, emitting the eggs and milt among the reeds and aquatic 

 plants. After eight to eighteen days thousands of young fish leave the 

 eggs. In order to spawn successfully the carp must not be disturbed 

 in the least, and it is absolutely necessary that no pike should be allowed 

 in the pond ; for otherwise the carp will not spawn. All these peculiari- 

 ties are of course well known to the pisciculturist, and he manages his 

 ponds by showing due regard to them. If he wishes to obtain young 

 fry from his carp, he is careful to keep pike out of his ponds; if, on the 

 other hand, he wants to raise large carp, he prevents them from spawn- 

 ing by placing a few pike'-in the pond. Much to the disgust of the carp 

 the pike plays the part assigned him with the indefat ; gableness and 

 energy of a policeman, keeping the carp constantly in motion and chas- 

 ing them through every part of the pond. The result is a very fine, 

 even breed of carp, with hardly any small fish, because the pike, pro- 

 ceeding in a most summary manner, will simply devour any fish which 

 are smaller in size than itself. 



The swiftness and strength of the pike are, however, also the cause of 

 the presence of this most dreaded of all fish-of-prey in all our lakes and 

 ponds, where it seriously interferes with the increase of the carp. As 

 Mr. von dem Borne says in his work Die Fischzucht (Pisciculture), 

 second edition, P. Parey, Berlin, 1881, the pike in one week eats a quan- 

 tity of fish equal to at least twice its own weight. Owing to the very 

 general occurrence of the pike, and the extremely small size of its fry, 

 it is absolutely impossible to keep it out of carp ponds which are fed by 

 a brook or other running water, and, mainly owing to this reason, the 

 raising of a large number of young carp, even in carefully managed 

 ponds, is connected with innumerable difficulties, of which Mr. von dem 

 Borne treats fully in his book. After the cause of the evil has been 

 recognized it is comparatively easy to remove it, viz, to select only such 

 ponds as spawning ponds which have absolutely no connection with 

 other waters. Such ponds are supplied with the necessary water either 

 from springs or by rain or snow. Nearly every farmer can have such a 



