610 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



TRIBUTARIES 



N 



O 



in 



TAUGHANNOCK Pf> 



MILES 



ITHACA 



Figure 24. — Cayuga Lake and its major tributaries show- 

 ing the five sampling sections of the lake. (Modified 

 from Galligan, 1950; footnote 10.) 



of lamprey wounds (table 47). To reduce bias 

 arising from size differences, only large trout (be- 

 tween 20 and 31 inches long) were employed in the 

 preparation of the table. As a further precaution 

 the data are given only for lake trout from sections 

 II and IV of Cayuga Lake to avoid bias from 

 locality differences. Lake trout in these two 

 areas are believed to form a single population. 

 According to Galligan, 10 large trout gather in 

 section IV during the summer and migrate to sec- 

 tion II in the fall for spawning. 



Feeding activity appeared to have reached a 

 peak during August and September. A decline in 

 feeding started in September and continued 

 through October and November. In July the 

 feeding activity was considerably less than maxi- 

 mum and was on a level with that for November. 



Table 46. — Incidence of sea lamprey wounds on lake trout 

 from 5 sections of Cayuga Lake 



[Boundaries of sections are shown in fig. 24] 



A chi-square test of independence for the 5 months 

 gave a value corresponding to p=0.03. It is to be 

 concluded that monthly variations in the percent- 

 age of wounded lake trout in the 20- to 31 -inch 

 size group are significant. 



Table 47. — Incidence of sea lamprey wounds on lake trout 

 during July-November 



(All trout were 20.0 to 30.9 inches long. 

 See fig. 24 for location of sections II and IV] 



10 The distribution of lake trout and associated species in Cayuga Lake, 

 by James P. Galligan. M.S. thesis, Cornell University, September 1951. 



Lake trout in the 13- to 19-inch length group 

 resembled those of the 20- to 31-inch group in 

 showing highest incidence of lamprey attacks 

 during August and September. 



The percentages of wounded lake trout in the 

 7- to 12-inch length group during July and August 

 were 22 and 23 percent, respectively. None, how- 

 ever, of the small number of specimens in this size 

 group captured during September, October, and 

 November possessed a lamprey wound. Since the 

 lampreys have more than doubled in length and 



