The Relation of Shellfish to Fish in Oneida Lake 31 



herbivorous animals, which in their turn, provide an abun- 

 dant food supply for the predaceous or carnivorous animals, 

 which are to a large extent fish. 



Production of Fish. An attempt has been made to deter- 

 mine the number of fish that this rich store of animal life 

 will feed. To do this it was necessary to know the amount 

 of food eaten in a period of time, as in a day or twenty-four 

 hours. Studies of such marine fish as the Plaice indicated 

 that its digestive canal is emptied about once in twenty-four 

 hours. The Goby, a small European fish, is found to empty 

 its alimentary canal in about six hours, the fish seeking its 

 food in the daytime. These marine fish, however, may not 

 be altogether comparable to our fresh-water species and these 

 fish are principally suggestive of methods for work which 

 should be done on fresh-water fish. 



During an investigation of the diseases of Oneida Lake fish, 

 many fish were caught in trap-nets, from which fish were 

 removed after intervals of 24, 48 and 72 hours. The results 

 of these studies suggested that the stomach may be emptied 

 in 24 hours, and the intestine in 48 hours. The percentage 

 of fish with empty stomachs increased rapidly with the time 

 interval of removing the fish from the net; 50 per cent 

 having full stomachs in the 24-hour interval, and about 13 

 per cent in the 48-hour interval. All had empty stomachs 

 in the 72-hour interval. 



It is known that the digestive powers of fish become 

 slower in cold weather, and it is probable that between the 

 months of November and March fish eat about two-thirds or 

 less of the amount of food eaten during the warmer months 

 of spring, summer and fall. In the examination of the 

 stomach and intestines of Oneida Lake fish it was found that 

 011 the average a fish with a full stomach contained about 

 115 invertebrate animals. If we assume that this amount 

 is a daily average, and that fish eat this amount for nine 

 months of the year, then the invertebrate animal life on the 

 bottom of the 1,164 acres examined in Lower South Bay and 

 vicinity are calculated to furnish food for 337,500 bottom 

 feeding fish. Predatory fish like the Pike Perch consume 



