2. The First Year . 



General . Upon the basis of regionally varying climate, local conditions, water 

 conditions, also considering the kind and number of available ponds, the experience 

 and enterprising spirit of the individvial fishbreeder, we have today four principal 

 methods for the breeding and raising of carps. In the following pages we are going 

 to discuss and to evaluate them. 



Breeding of carp and rearing of yearlings by means 



of hatching ponds, nursing ponds and rearing ponds 



(Dubisch method^. 



(a) Hatching . The Dubisch method (named after this fishbreeder, 1813-1888) uses 

 special ponds — sometimes called Dubisch ponds — for spawners as well as for spawning. 



These ponds must have a sunny exposure and must be well protected frcxn winds. It 

 is best to use porids of a size of 6 by 15 meters. AH around their dam rims a ditch 

 of about /^0 to 50 centimeters depth. Between the ditches rises the so-called spawning 

 board, slightly (roof-like) slanting at an angle of about 1:15, with a water depth of 

 from 20 to 30 centimeters. 



The ditches serve as an abode for the spawners, they facilitate their catching 

 (by two men with landing nets), as well as the fishing out of the brood, and also 

 facilitate the drainage of the ponds. 



ScMT.e carp fisheries use spawning ponds wher« the bottom drops gradually from the 

 point of inflow to the point of outflow (in German, the point of outflow is referred 

 to as the sluice "monk")* The bottom of the spawning pond is well covered with sweet 

 grasses into i*iich the eggs are deposited (see Fig. 17). Very long and especially 

 soft grass is mowed off before the spawning begins in order to reduce oxygen consumption. 



Some breeders prefer to raise harder grass — by keeping the bottom moist — and which 

 is less exposed to rotting and has not to be cut. Where grass is lacking, the bottom 

 may be covered with juniperus twigs or other suitable material. 



The bottom of a spawning pond must be absolutely impermeable so as not to require 

 a continuous inflow. The outflow (monk) must be carefully packed — best with clay — 

 between stowboards. The inflow of water must come from above in order to forestall a 

 rising of the brood. It is also indicated to protect the ponds against other brood or 

 brood enemies by means of sieves or filters at the point of inflow (see Fig. 8). 



As soon as the spawning process is over, the Dubisch ponds have to be disinfected 

 with quicklime in order to destroy eventual parasites and their intermediate stages. 

 They are then left to dry out until the spawning period of the following year. Two to 

 ten such ponds are required according to the size of the establishment. 



Occasionally only one such pond is used by even medium sized hatcheries, but a 

 number of ponds should be the absolute rule for more safety's sake, the more so since the 

 construction and upkeep of such ponds are not very costly. 



The inflowing v/ater is best taken from a shallow pond (not stored with fish, though) 

 which allows the water to warm up (Fig. 15). In order to avoid the accumulation of pre- 

 datory insect larvae, the ponds are filled up only shortly before the spavming starts. 

 Wild fish, which almost always are parasite carriers, and snails whicji frequently are 

 hosts to parasites in different stages of development are to be carefully kept out of 

 the feeder ponds so as not to bring them into the spawning ponds with the inflowing 

 "ater. To guard against diseases is better than to cure them l In the case of brood, 

 prophylaxis is especially indicated since brood diseases may eventually contaminate the 

 whole stock. 



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