2, The culture of adult trout . 



The fingerlings, during the first year, over the Tdnter and according to weather, 

 feeding and local conditions, have grown on the average to about 25 grams, 100 grams or 

 in rare cases even to 150 grams. They are separated into size classes and placed in 

 so-called "mast ponds", fingerling ponds, or maturing ponds (Fig. 38). If the mainten- 

 ance during the fingerling growth has been unsuitable, in too narrow ponds and too great 

 a stock density, in consequence of more unfavorable conditions of the space-factor- 

 complex, then maintenance in the mast pond is even more so. Over the winter the trout 

 fingerlings can still be kept pretty densely stocked in individual ponds, but beginning 

 the spring of the second year they will grow well only in larger ponds of at least 100 

 SQ.uare meters surface with steep banks, and a depth of 1.5 to 2 meters in a strong 

 through current and a stock density of about 25 to 50 fish per square meter. In order 

 to simulate the trout brook as much as possible, the mast ponds are elongated (for 

 instance /i x 25 meters). The water flows in and out through the narrow ends, so there 

 will be no dead angles where dirt can accumulate and decompose. 



The Schnede Trout Fishery, in order to emphasize the brook-like character of the 

 ponds, has arranged three trenches each 800 meters long and provided with strong currents 

 for masting. The trenches are separated in single divisions. This arrangement is not 

 always standard. It is probably better to construct the "brook" units shorter and as 

 individual ponds, because in case of disease occurrence or accidents each pond can be 

 kept individually. Of course separate inflow and outflow is advisable. Obviously, much 

 water is required if the trout are to have several ponds even without serial connection 

 (rig. 37) and the same water velocity as in the brook. In Schnede an entire small river 

 can be run through the trenches, the velocity is therefore strong. If each of the 800 

 meter long trenches were divided into 32 ponds, the velocity in a single pond could 

 only be weak. The living conditions, corresponding to the velocity of water would vary 

 more from the "natural". The hygienic conditions would, however, be more favorable, 

 and that must in the final analysis be the deciding factor. 



The rearing at a definite temperature is the more economical the quicker it succeeds, 

 since the consumption of maintenance food is so much greater the longer the rearing time 

 lasts. Accordingly, feeding must be done as frequently and constantly as possible to the 

 complete satiety of the trout. With rainbow trout, the faster growers can be used for 

 eating after a total rearing time of 16 months in the summer of the second year under 

 normal conditions in Germany. The last one quarter to one third pound table trout should 

 normally be "finished" after two to two and a half years. In pond fisheries infected 

 with gyrodactylus I have frequently observed that the last stragglers weighed only 50 

 grams after two years. Thereby the worst of the rainbow trout had already been eliminated. 



With so long a time of rearing, the loss of individuals (which in the second year 

 should not be over 5 to 10 percent), and also losses of maintenance food are too great. 

 With the appearance of spawning maturity in the second winter the individual losses often 

 suddenly increase strongly. The further rearing of these not even one-third pound poor 

 food evaluators into large fish, is mostly unprofitable. In fact the rule to be regarded 

 is: The rearing of sickly or weakly animals is unprofitable. The quicker they are 

 eliminated, the more is spared on work and food. 



Brook trout are best mixed up to 25 percent with rainbow trout, as they will then 

 go after food better. They can then be distinguished as in the first year from the 

 rainbow trout at a glance, because they like to remain in the depths of the ponds. 



The trout fishery's immediate rearing goal, according to Jaisle, is the production 

 of three sizes of table trout: 



Dinner - or menu trout of ;,, 130 to 170 grams. 



Portion - or a la Carte trout of 200 to 500 grams. 



"Salmon trout" or "Pond salmon" of 500 to 2000 grams. 



12^; 



