The Productivity of Fish Food in Oneida Lake 183 



INVERTEBRATES ASSOCIATED WITH THE MOL- 

 LUSCA IN LOWER SOUTH BAY AND VICINITY 



(jiiNKKAL Habi'iat Ri:latioxs 



The animal communities of Lc^wer South Bay and its 

 immediate vicinity include a large number of the groups of 

 fresh-water animals, sij^ of the phyla and 23 of the classes 

 or higher groups being well represented. The tables in the 

 chapter on the Composition of the Bottom Fauna indicate 

 the kinds of animals usually associated in these communities. 

 The remarks on quantitative methods of study with the mol- 

 lusks apply equally well to the associated animals. A single 

 dredging with the Walker dipper would usually bring up a 

 mass of filamentous alg^e fairly swarming with amphipods, 

 isopods, chironomid larvae, oligochaete worms, Cladocera, and 

 gastropod mollusks, indicating a rich fauna in both species 

 and individuals. Mollusks greatly outnumbered any other 

 single group of associated animals in number of individuals, 

 the total of each being about equal (9,335 mollusks and 9,105 

 associated animals). 



As in the mollusks, the associated animals bore a definite 

 relation to the filamentous algae (Cladophora, CEdogoniiuu, 

 Spirogyra), these plants providing a rich and abundant food 

 supply as well as a place of refuge from many enemies. The 

 oligochaete worms, chironomid larvae, and gastropod mollusks, 

 as well as some other animals, were of the same delicate pea 

 green tint as the algae, due to the great quantity of this plant 

 eaten. 



Relation to the Bottom. Associated animals bore a defi- 

 nite relation to the character of bottom, though, as with the 

 mollusks, the presence of filamentous algae modified this char- 

 acter to some extent. In Table No. 49 this relation of the 

 associated animals is shown in a diagram. We thus see that 

 14 species of animals live on all six varieties of bottom, 4 and 

 9 species respectively on five and four varieties of bottom, 

 17 species on three varieties of bottom, 19 species on two 

 varieties of bottom, and 56 species are limited to one kind of 



