Fro:ii the available literature and from my ovm experiences, I vfill quote here the 

 natural pond productivity — per annun — of certain fisheries and localities. These figui^s 

 are based upon the observations of many years. 



Bemeuchen (Neunark) about 100 kilograms per hectar. 



Spechthausen (near Eberswalde) " 100 " " " 



Wielenbach (Upper Bavaria) " 100 " " " 



In the fisheries in the "Lilneburger Heath" and in Lower Luaatia 

 about 50 kilograms per hectar. 



In the "Uckerraark" with good water but changeable soil, from 

 about 100 to 350 kilograms per hectar. 



Stadtforst in Saxony 100 kilograms per hectar. 



Uilitsch 65 " " " 



Geeste in 7/estphalia 50 " " " 



Dulmen in Westphalia 60 to 100 kilograms per hectar, 



Gemen in Westphalia 50 to 110 " " " 



In Upper Saxon Lusatia (with water of an A.C.C. of from 0,1 to 0.^5) 



2.5 to 90 kilograms per hectar. 



In Upper Saxon Lusatia (with water of an A.C.C. of from 0.1 to 0,95) 



25 to 135 kilograms per hectar. 



In Upper Saxon Lusatia (vrLth a constant A.C.C. of at least 0.5) 



135 to 210 kilograms per hectar. 



Scheyem (Lower Bavaria) an average of 317 kilograms per hectar. 



Rampsau (near Regensburg) an average of 117 kilograms per hectar. 



The classification of ponds (on productivity) is bound up, of course, with stock 

 conditions. Just as the returns of a field depend upon quality and quantity of seed, so 

 the productivity of a pond depends upon the species, and "race", the state of health, 

 the number and the size of fish. 



Tables 17 and 18 will better illustrate the points that have been discussed. 



Table 17. 



Classification (on productivity) of carp ponds, stocked with 2 year old carp 

 of normal weight (350 grams) and increasing in weight as listed under B. 



1. Class 2. Class 3. Class C. Class 



A. 



Natural increase in ^^0 to 200 200 to 100 100 to 50 50 to 25 

 kilograms per hectar. 



B. 



Normal basic weight 1000 to 12 50 1000 1000 to 750 750 

 increase per fish 

 (in grams). 



By exclusive stocking with carp yearlings (weight increase 300 grams) the natural 

 productivity is in average about UO percent higher, by stocking with brook trout 

 or rainbow trout (weight increase 120 grams) in average by about ^0 percent lower. 

 Mixed stock and deviation from the normal weight (at time of stocking) will change 

 the rate of natural increase (A) per hectar and annvim. 



127 



