140 Conservation Department 



VII. PLANKTON STUDIES OF CAYUGA, SENECA AND 

 ONEIDA LAKES 



By W. C. Mukxscher, 



Assistant Professor of Botany, Cornell University 



In a biological survey of a body of water for the purpose of 

 determining the factors and conditions which contribute to the 

 production of fish, the source of fish food is of prime importance. 

 In this connection the plankton organisms, those small free- 

 swimming or suspended organisms occurring in the water, furnish, 

 directly or indirectly, one of the chief sources of food for fish and 

 other animals that are eaten by the fish. 1 



The following members of the survey staff assisted in this undertaking: 

 Dr. Gertrude E. Douglas, Albany State Teachers' College, Mr. Paul R. Burk- 

 holder, Cornell University, Mr. Willis L. Tressler, University of Wisconsin, 

 Mr. Sidney Britten, Syracuse University, Mr. F. E. Wagner, Rensselaer 

 Polytechnic Institute. This work was greatly facilitated through the co-opera- 

 tion of Cornell University: the Department of Botany made available a lab- 

 oratory which served as general headquarters from June 15 to September 15, 

 1927; the Laboratory of Plant Physiology granted the use of equipment and 

 apparatus necessary for certain chemical work and gravimetric determinations 

 of plankton ; the Department of Zoology granted the use of the University boat 

 house on Cayuga lake for the storage of boats and other equipment. 



The most important lakes of the Oswego watershed are the 

 Finger lakes and Oneida lake. The limnological studies reported 

 by Birge and Juday, 2 , 3 already furnished a general preliminary 

 survey of the plankton life of the Finger lakes though not of 

 Oneida lake. 



The amount of time and the facilities available for plankton 

 studies precluded the possibility of making very extended studies 

 on all the lakes in the Oswego river watershed. It seemed that, 

 under the circumstances, the most worth while results could be 

 obtained by concentrating the plankton work on a few lakes. 

 Plankton studies were therefore conducted on three lakes ; Cayuga 

 and Seneca, the largest of the deep lakes and Oneida, the only 

 large shallow lake in the Oswego watershed. 



The aim of this study was to make available more information 

 concerning the abundance, vertical and horizontal distribution, 

 and periodicity of the various kinds of plankton organisms in 

 each lake. An attempt was also made to gain some idea of the 

 condition of the environment under which the plankton organisms 

 occur by measuring some of the factors such as temperature, 

 transparency, dissolved gases, and reaction of the water. 



By limiting the work to three lakes it was possible to make the 

 observations and take samples approximately every two weeks in 

 Oneida and Cayuga lakes, and once a month in Seneca lake, from 



i For discussion of the larger vegetation sec Appendix XII. 



2 Birge, E. A., and Judav, C. A. linnologica] study of the Finger L.\kes 

 of New York. U. S. Bull, of the Bur. of Fisheries. 32: 525-009. 1912. 



:: — Further limnological observations on the Finger lakes of New 



York. Ibid. 37: 211-252. 1919-20. 



