2(3 College of Forestry 



catfish feed upon clams or mussels. In Oneida Lake, nine 

 fish are known to lie susceptible to infection by mussel glo- 

 chidia. These are Green Sunfish, Bluegill, Strawberry Bass, 

 White Bass, Catfish, Yellow Perch, Large-mouth Black Bass, 

 Rock Bass, and Pumpkinseed. This subject has not the 

 economic significance in Oneida Lake, or, indeed, in Xew 

 York State, that it has in the Middle West, where the button 

 factories are dependent upon, the mussels for their raw 

 material. 



Recent studies (C. B. Wilson, Bull. U. S. Bureau of Fish- 

 eries, Vol. 34, pp. 329-374,' 1916) on the small crustacean 

 parasites, known as copepods, which infest the gills and fins 

 of many fish, have shown that there is a definite relation 

 between these parasites, which are harmful to the fish, and 

 the young mussels or glochidia which apparently do the fish 

 no harm. It was found that where the gills were already 

 infected with young mussels they are practically immune 

 from attacks by the harmful copepod parasites, showing that 

 the presence of the glochidia is of advantage to the fish. At 

 the United States Biological Station at Fairport, Iowa, 

 where experiments on the artificial infection of fish by glo- 

 chidia have been conducted on a large scale, it has been 

 found that by infecting fish with the glochidia they may be 

 rendered immune for a time from the attacks of the copepod 

 parasites. It was also observed that where a fish w r as carry- 

 ing the parasitic copepods it could not be infected with glo- 

 chidia. Parasitic copepods have been observed on the gills 

 of several species of Oneida Lake fish, and of the 50 species 

 of fish inhabiting this lake, 17 are known to carry copepod 

 parasites and 11 mussel glochidia, in other localities, and it 

 is apparent that the mussels, of which 12 species have been 

 found in Oneida Lake, are of considerable importance to the 

 fish life of these waters. It is possible that the presence of 

 these young mussels or glochidia has made the fish of this 

 lake more or less immune to the attacks of parasitic copepods. 



