The Productivity of Fish Food in Oneida Lake 45 



THE PLANT ASSOCIATIONS OF LOWER SOUTH 



BAY 



Introduction 



Fish and most other a(|uatic animals are absolutely depend- 

 ent, in the ultimate analysis, upon plant life for their food and 

 development. Embody ('15, p. 239) admirably sums up the 

 reasons for this dependence under five heads, as follows : 



1. They constitute the principal food of a few fishes. 



2. Directly or indirectly they furnish food and shelter to a host of 



small organisms that are eaten by fishes. 



3. They are necessary in the spawning activities of certain fishes. 



4. They purify the water by taking obnoxious substances including 



carbonic acid gas exhaled by aquatic animals, and by giving 

 back oxygen. 



5. They protect the water underneath them and the pond bottom 



from the heat of the sim. 



A sixth reason might be added, that they provide a binding 

 medium for holding the inaterial of the bottom together. 



Titcomb ('09, p. 6) clearly indicates the great value of plant 

 life when he says: " Through the necessity for natural food, 

 then, comes the primary importance of aquatic plants in pond 

 culture. All animal life is dependent, directly or indirectly, 

 upon plant life, the minute forms as well as many of the larger 

 feeding directly upon plants, and the herbivorous species in 

 turn serving as food for the carnivorous. The young fishes 

 feed upon small crustaceans and other forms which are abun- 

 dant only in an environment with abundant vegetation. 

 Aquatic plants are therefore the food-producing agency in 

 pond-culture, and are accordingly indispensable." Titcomb 

 also rates plants as of great value in properly aerating the body 

 of water and in holding the soil of the bottom in place. 



Decaying plants are objectionable because of certain poison- 

 ous subatances thrown off, and a plant may also be obnoxious 

 because of its too luxuriant growth which chokes the water 

 and makes an unfavorable environment for fish as well as for 



