52 Conservation Department 



The Bottom Fauna. — During our survey a large part of our 

 efforts were directed to the study of the bottom fauna to discover 

 the principal source of the primary fish food in the lake. Six hun- 

 dred and thirty-two samples of the bottom were taken with the 

 Ekman dredge during the three months and carefully analyzed. 

 To supplement these studies 212 samples were taken with the scoop 

 dredge in localities where the Ekman could not be worked satis- 

 factorily and several hundred samples* were taken in the shal- 

 lows near shore with a Needham dredge. 



We find as a result of this work that in the shallow water of all 

 the lakes there is a fair supply of snails, bivalves, and insect larvae, 

 principally mayflies, caddisflies and midges, ranging to a depth of 

 50 feet. The abundance of these forms in shallow water, however, 

 is not sufficient to supply a preponderant fauna of shallow water 



Lowering Ekman dredge for a sample of lake bottom 



fishes. The minnows, likewise, which are mostly confined to the 

 shallow water of the lake are not abundant except in a few favored 

 localities. 



In the deeper waters we find in all the lakes a plentiful supply 

 of the small .crustacean (Pontoporeia hoyi),oi chironomus larvae, 

 a fair supply of small worms (OligocJiaetes) and a fair supply of 

 bivalves. (Spliaerium) . Likewise in most of the lakes near the 

 bottom a fairly plentiful supply of the small crustacean (Mysis). 

 These forms are the food of young trout, whitefish, etc., and are 

 often eaten by the larger fish when other supplies fail. In Keuka, 

 Cayuga and Skaneateles lakes we took specimens of Pontoporeia 

 filicornix. 



* The determination of the organisms captured was the work of Dr. Thomas 

 Smyth of South Carolina University. 



