Naturally this division into large classes is very arbitrary, but despite this it 

 gives a good general view. It mxist not be forgotten that divisions serve the reader only 

 as a temporary introduction but they may actually be erased by transitions. 



Taken accurately the trout pond industry is included in the figures of table 10 for 

 carjj-pond industry, but the error is only very slight, since medium trout pond industries 

 are only about 0.5-A hectars in size and the largest German and European trout fishery of 

 Schnede covers chly 15 hectars (about 57 acres). 



Of all inland waters (excluding Haffs) of Germany, the area of paids amounts to only 

 6.6 percent. Tfhile this figure is small, it does not properly express the iu^wrtance of 

 pond culture forpisci culture as a whole. 



In the first place, ponds produce about twice as many fish as rivers and about three 

 times as much as lakes (per like area). Furthermore it must be kept in mind that pond. 

 fisheries are conducted intensively and practically without waste, making use of all 

 available resources to the f\illest extent. This, of course, is never the case in free 

 waters, such as rivers and lakes. 



The total production of adult trout in Germany, d\iring the years 1930 and 1931 

 amounted to 15,000 dozen, while in 1931, 65,000 dozen of carps were produced. 



By adding to these figiires the amount of brood fish and of fish raised for special 

 purposes, we find that the total production of carp and trout pond fisheries in Gennany 

 amounts to about 12 percent of the total fresh-water fish production in Germany (by 

 figuring this total annual production at 125,000,000 kilograms). 



It must further be kept in mind that the amount of fingerlings, furnished by carp, 

 tench and trout hatcheries for open waters cannot be evaluated by mere weight, because 

 regulated operation in many natural waters depends on procuring first class healthy stock 

 from pond fisheries. 



Finally, pond culture — from the theoretical standpoint — is the great educator in all 

 matters of piscicultiire and has thus rendered invaluable service to fishery as a whole. 



In the division according to fishery size classes, it should be further stated that 

 the heaviest fry production is with the larger medium fisheries, Smnli and large fisheries 

 produce mostly food fishes. Large fisheries, as mentioned above, frequently purchase 

 additional stock material, small fisheries must practically always purchase their stock. 

 Ctily seldom do small fisheries grow younger age classes for neighboring large fisheries. 

 The small pond fishery (see Section XIII) as a rvle is not a hatchery, but is concerned 

 only vdth fish maintenance, especially with carp maintenance. Small pond fisheries pre- 

 dominate in East Pnissia, and in the central, southern and western parts of Germany, 



Chapter IV 



CAHP FISHERIES 



A. The carp. Market denands. Types of scale formation. Objects of 



rearing. Races of carps. Breeding of carps through rational selection 



from the viewpoints of race purity and of best productivity. 



The main commercial commodity giving the name to the carp-pond industry, is the carp 

 ( Cyprinus carpio L). A knowledge of its form, external markings and body structure as 

 shown in Fig. lA is taken for granted. The confusion of the carp with other fishes can 

 only occur in the case of the crucian carp which has a certain resemblance to the carp. 

 In the possession of ^ barbels on the upper jaw, which even at the age of 25 days attain 

 a length of 3.2 cm. (Stankovitsch, 1921) the carp may be distinguished from the crucian 

 carp by closer observation. It is therefore con^Dletely unfounded, when small-pond oper- 

 ators take the viewpoint that it would be unsuitable to buy carp for stock because they 

 cannot be distinguished from the poorly growing crucian (see Crucian carp). 



71 



