On the other hand, it is possible that organisms that are more difficult to detect 

 on the part of fishes, multiply moie rapidly and fill the niches in the habitat. Thus, 

 new colonies of larvae corifora to the tendency of all living organisms and multiply in 

 relation to existing conditions of life and of sustenance. 



Therefore, we may assume th^t a thickly populated pond in the course of a year will 

 produce — niunerically — more aquatics than a pond of like biological production category 

 but of lesser density of stock. 



V.lien examining the influence of amount of stock upon aquatic life, another pojjit is 

 finally to be considered. Attention vas called to it already by "Walter, but it has not 

 been mentioned here so far. 



The reduction in the nonconsumed remainder of aquatics — due to a greater density of 

 stock — brings forth a secondary check in the d evelopment and perhaps also in the pro- 

 pagation of certain aquatics . Theoretically, one can even assume a reaction, stretching 

 into the following year, although I have been unable to confirm this by experiment. 



On the other hand, general conditions favor propagation upon the grandest scale, 

 and a check in the case of larvae, for instance, is almost inconceivable. Hence, it 

 follows that the nutritional conditions frora the limiting factor of mass development and 

 that in newly formed ponds the full productivity or crop of individuals will be produced 

 in a fevf days in sujniner. 



And then again, the development of individual aquatics will undoubtedly be chedced 

 with an increasin,^ popiilation of the pond, and for the simple reason that a vast number of 

 aquatics will be eaten up vrtiile in full gixiwth. 



It is characteristic that we note in pond 6 (Jig. 6) a ten^aorary absence of the 

 large larvae of Chironomidae ^ which fish can hardly ever overlook. Even the individual 

 weijht of such a larvae — in July — is remarkably lov; in pond 6, in comparison Ydth the other 

 ponds. But altogether, one siiould not attach too much importance to such losses in food- 

 stuffs. ViTiat has been stated here, especially in regard to larvae of Chironomidae pertains 

 also, of course, to all other but less important aquatics. 



upon the basis of the discussed investigations, I set forth again a differentiation of 

 aquatic productivity as a whole during the period of summer cultivation with regard to 

 varjTJig degrees of stock. Chart VII will illustrate the points under discussion. 



Individual Growlh 



Fir. 7. Semi-scheinatic projection of the relation between density of fish 

 stocl:, increase of carp stock, consuTied and noncons^amed lot of aquatics, 

 and the absorption of detected food. (r"i;jures based, as far as possible, 

 upon experiments made by the author.) 



39 



