incurred, by transferring the broodlinga directly into the larger ponds are rather great 

 in these ponds, the rearing ponds have to be stocked with about iiO,000 fishes per hectar. 



Where nursing ponds are lacking but the Dubisch method is preferred, the fishbreeder 

 according to Schaeperclaus can use the rearing ponds as nursing ponds by simply stocking 

 and treating them accordingly. For this purpose they are stocked sparingly and thus 

 handled as nursing ponds. 



After four weeks, he fishes them out, refills them and restocks them with nursed 

 brood. Just as if he was transferring the brood from a regular nursing pond into a rear- 

 ing pond. Wien water is scarce he will have to forego the fishing-out and will then 

 estimate the production results from sample catches. Afterwards, the ponds are filled 

 with the complete amount of water. 



The raising of yearlings is handled in all other respects as in the case of the 

 Dubisch method. 



The raising of carp fingerlings and of yearlings in larger 

 spawning ponds (also used as nursing ponds) 

 and in rearing ponds. 



This method omits, so to speak, the special spawning pond of the Dubisch system. 

 The spawners are set out in nursing ponds of from about 5 to 25 ares (about 1/8 to 2/3 

 acres), and are left to spawn. After the fishing-out of the parent fishes, the brood is 

 left for 8 to lA days in the enlarged spawning ponds and is then transferred to the 

 rearing ponds (the broodlings are then about 1 to 2 centimeters long). The losses will 

 be rather constant and the fishing-out of the yearlings can be undertaken with advantage 

 in the spring, omitting the use of special nursing ponds. 



PxxDvided that the broodlings do receive the proper care in the spawning ponds, the 

 method can be recommended where water is scarce and spawning ponds are lacking. 



Pursuing this idea further, one might arrive at the conclusion that carp could be 

 raised with just one big pond by continually filling and draining it, using it for spawn- 

 ing and nursing and rearing alternately. 



This is impossible on account of the quickly accumulating layers of mud and the lack 

 of grass in the deeper parts, near the outlet sluice. But the main obstacle against such 

 a procedure would lie in the great number of spawners required. For 10 ares (about l/^ 

 acre), one would need 5 to 7 females and 10 to Li males if the requirement is to be cover- 

 ed by one or two spawning ponds and the spawning is to be successful. 



Hatching of carp and raising of yearlings 

 by means of rearing ponds only. 



This old method is still applied occasionally today. It is especially to be found 

 now and then in very large fisheries where failures in single ponds do not play so large 

 a role for the entire fishery and vrtiere on the other hand there is frequently a lack of 

 reliable working forces which control and carefully handle the nursing method. The 

 spawning carps are placed about 5 sets per hectar into the large rearing ponds irfiere 

 they are to spawn, 



I am giving this method here principally to warn against its regular or exclusive 

 application despite a good health condition attained in the yearling carps, because it 

 leads to a primitive management given to chance. The size and amount of yearling carps 

 attained can never be safely estimated in advance. Von dem Borne announces that in 

 such a pond he received yields of 180,000 yearlings and then again of only 8,000 

 yearlings . 



87 



