For a time, the mirror-carp was greatly in demand but is now mostly replaced by 

 the leather carp . 



This sub-variety is almost without any scales whatever. Only a few will be found 

 at the bases of the fins. It must be borne in mind that these various kinds of carp do 

 not constitute different races or species, but merely sport varieties. We have similar 

 variations among Roach, Tench and Crucian (Wlese), and these variations do not react 

 upon other characteristics, such as growth, for instance, as was demonstrated qiaite 

 recently by Sklower, through experiments conducted in East Prussia, 



The experiments by Rossler — conducted for six c<yitinuous years — have shown that at 

 times the "scalers", and at other times, the mirror-carps showed better increases in 

 growth. 



Considering the above-stated market demands, the carp breeder also considers the 

 following points: 



First class fish shall: 



(1) Grow fast, since this makes for food saving. They shall grow so fast 

 that the table weight is reached before the fish mature, i.e. within 

 three summers or fcnir summers at the utmost. The possibility of 

 their spawning would con?)licate their culture out of the ordinary. 



(2) Use the natural food to the best possible extent and artificial food 



to good advantage, in other words, they shall have a good "intelligence 

 factor" . 



(3) Be resistant against disease, against temporarily bad water conditions 

 (slightly sour water), against drainage, transportation and hibernation. 

 They shall be hard to see and to find by enemies and thieves. 



(^) Under like environmaital conditions within one and the same "race", 



show like and strongly inherent genotypical characteristics. Only then 

 can one speak of a race (species) and only then is it possible to achieve 

 similarity in the table product, 



(5) Be raised in various and variously endowed races, adapted to regional 

 conditions. It is practically impossible to breed a race with hereditary 

 characteristics which eventually become so paratypical and adaptable as 

 to develop a race which under all and the most differing conditions 

 (rough and mild climate), even by slightly sour water will still produce 

 a first class table fish. In order to be able to distinguish between 

 the different races, i.e. stock of different characteristics, it is 

 advisable to inbreed into each different race an easily distinguishable 

 external characteristic, 



(6) Be well propagating and produce resistant brood, easy to raise. 



Like Kronacher, I understand by "race" a group of fish, best suited from the economical 

 viewpoint for certain conditions, and which under like conditions will transmit their most 

 important and outstanding characteristics to their progeny. Of course, to rear an absolutely 

 pure race is in practice almost in^jossible, but with planned purpose one will come as near 

 to it as can be reasonably expected. 



Out of the total purposes of selection, it follows o.ntrary to earlier attempts, that 

 no value needs to be placed for example on the height of the back, which even led to the 

 selection of spawn carps with shortened or curved (Kypholordoic) spinal columns. 



73 



