606 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



The number of sea lamprey marks (both scars 

 and wounds) increased progressively with body 

 length (tables 42, 43, and 44). Trout between 5 

 and 9 inches long rarely had suffered lamprey at- 

 tacks. Trout from 9 to 16 inches in length showed 

 a gradually increasing rate of attack. At a length 



of approximately 16 inches the apparent rate of 

 attack increased rapidly and reached its peak of 

 roughly 11 marks per trout for the largest speci- 

 mens, which were approximately 30 inches long. 



It may be asked whether sea lampreys prefer 

 large lake trout as their host, or whether they feed 



Table 42. — Incidence of sea lamprey attacks on lake trout from Cayuga Lake, 1949 



1 Scars and wounds combined. 



Table 43. — Incidence of sea lamprey attacks on lake trout from Cayuga Lake, 1950 



1 Scars and wounds combined. 



