Biological Survey — Oswego Watershed 57 



content and various other chemical conditions must be considered 

 when determining the stocking policy for the lake. Fortunately 

 all these Finger lakes, with the exception of Otisco, have favorable 

 water for the growth of lake trout, cisco, whitefish and pike-perch 

 as well as bass. In Otisco in mid-summer the deeper portions of 

 the lake, as shown in the table,* are devoid of oxygen sufficient to 

 support any fish. Consequently the deep water fishes should not 

 be planted in Otisco but shallow water fishes, such as pickerel, 

 perch, pike-perch, bass, and pike should thrive there. We have 

 been unable to find any condition of the water which would ex- 

 plain the scarcity of trout in Cayuga lake and believe it should be 

 attributed not to the condition of the water but to the enemies of 

 the fish, to illegal fishing and to mistakes in planting. 



(10) Food supply both for the young fish and the mature indi- 

 viduals is the prime requisite next to the oxygen supply. There is 

 no reason, except the burbot, and absence of alewives why Canan- 

 daigua lake should not be nearly as good a lake for lake trout as 

 Keuka. There is abundance of food on the bottom for young trout 

 but the older fish have difficulty in obtaining the small fish which 

 make up 98% of their food. The cisco is scarce, the alewife is 

 absent, the smelt, which has been introduced there during the 

 last few years, has not multiplied sufficiently. We believe that 

 a good supply of alewives in Canandaigua would increase tremen- 

 dously the abundance of trout in those waters. The same is true 

 of Owasco lake where the cisco is too scarce to furnish food for 

 the trout, The smelt has been introduced recently but is not yet 

 abundant. The trout which we took from Owasco lake were almost 

 starved because of the scarcity of proper food for mature fish. 

 They had been feeding mostly on mysis, which is a food adapted 

 especially to young trout, These illustrations should make clear 

 that a proper food supply is the first consideration in waters which 

 are to be stocked and everything possible should be done to in- 

 crease the food supply of game fish. 



General Conditions in the Various Lakes. — In all the lakes 

 examined, except Otisco, the temperature and oxygen content of 

 the water is favorable for lake trout and whitefish. The shallows 

 in all the lakes are fairly well adapted to the black bass and the 

 perch. In all the lakes the tributary streams have been seriously 

 affected by the destruction of the original forest cover and agri- 

 cultural improvements so that they furnish small encouragement 

 to the suckers and many species of minnows which formerly bred 

 in them successfully. In all the lakes weed beds are poorly dis- 

 tributed except at the head of each lake and in sheltered bays and 

 shallows which are sometimes found along the shore but more often 

 at the foot of the lake. Consequently there is a small acreage 

 available for weed-inhabiting fishes as compared with the large 

 extent of the lake. Therefore fishes which range widely in the lake 

 and are either bottom feeders, plankton feeders or feeders on 

 smaller fishes which feed on plankton are the best adapted for 

 encouragement in these waters. 



* See pp. 117 and 131. 



