ABSTRACT 



A life history study of the sea lamprey, Petromyzon marinus Linnaeus, in Cayuga 

 Lake, N.Y., was conducted during 1950, 1951, and 1952. One of the major objec- 

 tives was to obtain biological data concerning this endemic stock of sea lampreys 

 for comparison with the newly established stocks in the Great Lakes. 



Sexually mature sea lampreys captured on their spawning migration in Cayuga 

 Inlet were the basis of much of this study. Such items as meristic counts, body 

 proportions, body color, sex ratios, lengths and weights, fecundity, rate of upstream 

 travel, effect of dams in retarding upstream movement, nesting habits, parasites, 

 predators, estimates of abundance, and morphological changes were based on 

 mature upstream migrants. Sea lampreys were procured by weir and trap opera- 

 tions and captured by hand. Tagging and marking programs each spring made 

 it possible to determine movements and morphological changes of individual lam- 

 preys, in addition to estimating the number of upstream migrants. 



Growth of parasitic-phase sea lampreys was estimated from measurements of 

 specimens captured in Cayuga Inlet and Cayuga Lake proper. 



The incubation period of lamprey eggs and the habits of ammocoetes and trans- 

 forming lampreys were ascertained from specimens kept in hatchery troughs and 

 raceways. Length-frequency and weight-frequency distributions, together with the 

 length-weight regression, of ammocoetes from Cayuga Inlet were utilized for esti- 

 mating the duration of their larval life. 



Lake trout, Salvelinus n. namaycush (Walbaum), from Cayuga Lake and Seneca 

 Lake were the subject of an inquiry into the effects of sea lamprey attacks. 

 Incidence of sea lamprey attacks on the white sucker, Catostomus c. commersoni 

 (Lacepede), was investigated. 



Three methods are suggested for reducing the number of sea lampreys in Cayuga 

 Lake. 



