(5) Under mixed stock conditions (2 year old caip and yearliftgs) the weight 

 increase of the minority grade is greater, and the increase of the 

 majority class is less, that is, in comparison. Tench stock, when 

 added to c&rp stock will bring down the increase of carp through lower- 

 ing the rate of increase per space unit. If more than three 1 year tench 

 are placed to one yearling carp, any advantages of tench stocking are lost. 

 True, the weight increase of carp is raised but the increase per space 

 unit is lowered below normal (according to Walter). 



(6) Overstocking increases the yield per surface unit but the individual weight 

 increase naturally is considerably retarded. Vrith an eight-fold over stock- 

 ing with yearling carp, the surface yield increases three-fold and it was 

 found by Walter, that the individual growth, which normally should be i.00 

 grams, v;as only 16/+ grams. The application of this rule can only pay 



practically when carp are artificially retarded for three years and used in 

 the fourth year as three year olds weighing about 350 grams, and used 

 like two year old stock. After effects on food animal production do not 

 occur in the following year with overstocking, which has been revealed to 

 me by experiments in the fishery of the Forest Academy at Eberswalde. 

 Theoretically such an undesirable after effect would be thoroughly con- 

 ceivable . 



(7) The increase of stock density resulting from feeding in carp ponds with 

 stock food causes a considerably better evaluation of the available 

 natural food. The success of the feeding does not ultimately depend on 

 this. One half to two thirds of the total nutrition in this way is repre- 

 sented by natural food in the feeding management. Only under such con- 

 ditions is the food well evaluated. The yield increase by pond fertiliz- 

 ation is also largely due to the increase of stock density by means of the 

 food stock. 



The number of stock for carp ponds with feeding is calculated in the same 

 way from the total grovrth increase (table 20), which in this case equals 

 the sum of the natural growth increase and the food growth increase. 



For cases where no special calculation of the stock figure is to be carried 

 out, I have elsewhere given guide figures. I shall again give them in 

 Table 19, and also average stock fig\ires for carp ponds. These figures may 

 be valuable to the small pond operator and to the beginner wtio wishes to 

 avoid calculations by the stock formula. I must emphasize that Table 19 

 deals only v;lth approximate average figures. 



In setting up the stock plan it is obviously necessary to consider the characteristics 

 of each pond, its freedom from pike, the possible penetration of wild fishes and all other 

 factors which would make a stock regulation illusory. Each pond must have its own most 

 suitable stock. The technique of stocking is extremely simple. Previous determination of 

 the number and weight of the fish to be placed is obviously necessary after what has been 

 said and in the interest of good bookkeeping, which alone allows the collection of 

 experiences. 



The ponds must be amply covered at the right time before the fish planting. Large 

 ponds in some circumstances are kept closed for weeks before the planting of fish. Stock 

 to be purchased should be ordered in the previous autumn, and the transportation should 

 be Trell prepared so that no unpleasant surprises can occur. The only thing remaining to 

 be watched, is the avoidance of temperature differences, especially with the youn brood, 

 and thorough distribution of fishes (especially brood) is setting out at the shore. 



Larger fishes are most conveniently transferred to the pond with a wooden or better 

 a galvanized iron slide. In this way barrels can be poured out from the top of the dam. 

 By using sack-linen hoses, the barrels can even be tipped over on the wagon. The fish 

 are carried unharmed through the hoses into the pond. A distribution of larger fishes 

 during the setting out is generally superfluous. 



