The Prodncliviiy of Fish Food in Oneida Lake 203 



RELATION OF THE FOOD SUPPLY TO THE FISH 

 POPULATION OF LOWER SOUTH BAY 



"When wc consider that the mockrn or ratlier quite recent — 

 investigations which I have called Valuation Investigations date hack 

 but some few years, and that it has been necessary to invent entirely 

 new apparatus for the study of marine bottom fauna, it will readily be 

 recognized that these investigations are as yet only in their infancy, 

 and far from being completed. Wc still lack figures of the annual 

 production of the various species of animals in different waters, and in 

 many cases it may be that such figures will be difficult to procure at all." 



Petkkskn '15, p. 29. 



hi the chapter 011 the Composition of the Bottom Fauna 

 tlie mass of animal Hfe per square unit of bottom and for the 

 entire area examined (durinj^ the month of July) has been 

 given. The value of this invertebrate life to the fish fauna 

 as food is the object sought in this investigation. We wish to 

 know how many food and game fish this amount of animal 

 life will support. This problem is complicated because of the 

 diversity of food habits amorig the fish population. A number 

 of fish are vegetable eaters, some are predaceous, living on 

 other smaller fish, but the great majority- subsist upon the 

 animals noted in the previous pages, and even those fish living 

 on other fish depend in the tiltimate analysis upon invertebrate 

 animals through the food of the fish preyed upon. Before 

 considering the intimate relation between the food supply and 

 the fish fauna it will be necessary to know something of the 

 annual production of this dependent life, and of the animals 

 other than fish, that also prey upon this life. 



Foot) Habits of Invektebkatf, Animals 



Blegvad ('15, pp. 41-78) has carefully studied the general 

 conditions and food among the communities of the inverte- 

 brate animals inhabiting the bottom of Danish marine waters. 

 This writer made stomach examinations of nearly all the com- 

 mon invertebrate animals living on the sea bottom (pp. 52-73) ; 

 many specimens of each species were studied. As a result 

 of these investigations the animals of this region are divided 



