14 



PLANTS IN PONDFISH CULTURE. 



plant associations, and it is through a more complete understanding 

 of such associations that the method of rationing the ponds to in- 

 crease their productivity by natural means can be approached. 



SUMMARY. 



1. Chironomid larvae are among the most important single items 

 in the dietary of young bass. 



2. The identification of the food content and plant associations of 

 the chironomids indicates the importance of cultivating certain 

 algal forms in the ponds to provide adequate forage requirements. 



3. Mat-forming algse of certain types provide valuable forage 

 areas for chironomids and cladocerans. 



4. The Bosmina-Volvox association is of special importance in 

 providing the first forage materials for the bass fry and the young 

 bluegill. 



5. The Scapholeberis-Mougeotia association is important in pro- 

 viding a later food for the advanced fry stage. 



6. The Daphnia-Aphanizomenon association develops a heavy cul- 

 ture of daphnia. 



7. Plants are of importance directly in supplying a high percentage 

 of food to the advanced fry of the buffalofish. 



8. The blunt-nosed minnow in a pond habitat subsists mainly upon 

 plants. 



9. The rationing of ponds for a continuous and abundant supply 

 of natural forage must depend upon a more precise knowledge of 

 the animal and plant associations. 



TABLES. 



[Note. — All figures in the tables referring to food content represent volumetric per- 

 centage estimates. Measurements in lengths are given in millimeters and exclude the 

 caudsd) fin.] 



Table 1. — Inventory of Aquatic Plants in Certain Ponds of Series B and D, 



Fairpobt, Iowa." 



[P means present; A means present in abundance.] 



Aquatic plants. 



Flagellates: Euglena sanguinea. 

 Blue-green algEe: 



Aphanizomenon flos-aquse.. 



Microcystis 



Clathrocystis 



CoelosphEerium 



Merismopedium 



Oscillatoria 



Lyngbya martensiana 



Anabsena circinalis 



Anabfena flos-aquEE 



Kivularia natans 



Diatoms: 



Navicula 



S vnedra 



Pleurosigma 



Cocconeis 



Melosira 



Tabellaria fenestrata 



Fragilaria 



Gomphonema 



Amphora 



June, 1917. 



Pond 

 ID. 



Pond 

 2D. 



Pond 

 3D. 



Pond 

 8D. 



Pond 

 16B. 



« Inventory not exhaustive but sufilciently detailed to serve as a working basis. 



June, 

 1918. 



Pond 

 9D. 



