600 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



Figure 20. — Length-weight relationship of sea lamprey ammocoetes and transforming specimens taken from Cayuga 

 Inlet during August. Regression formulas: for ammocoetes, Y= 1.63-0.0354 X + 0.0004 X 2 ; for transforming 

 lampreys, K=5.02 + 0.1667 X-0.0003 XK 



ammocoetes captured in Cayuga Inlet were marked 

 with cadmium sulfide or mercuric sulfide, as de- 

 scribed by Wigley (1952), and installed in an out- 

 door hatchery raceway. The raceway bottom was 

 covered with several inches of sand and silt, and 

 water was supplied from Cascadilla Creek. 

 Marked specimens with body lengths of 5.43, 5.43, 

 5.59, 5.91, and 6.02 inches (approximately the 

 length of age group VI) on August 24, 1951, 

 began transforming in August 1952. Further- 

 more, marked specimens 4.80, 4.80, 4.92, 4.92, and 

 5.12 inches long (about the length of age group V) 

 on August 6, 1951, kept in the same raceway with 

 the previous group, did not transform in 1952. 



These specimens are plotted in the length- and 

 weight-frequencies of figures 17 and 19. This in- 

 formation and the modes indicated in all length- 

 and weight-frequency distributions not only give 

 convincing evidence that the recognition of age 

 group VI is valid, but lends support to the valida- 

 tion of recognizing other modes in the length- and 

 weight-frequency distributions. 



Although the present study has yielded the 

 strongest evidence for a larval life of 7 years, as 

 compared with 3 to 5 years propounded by pre- 

 vious investigators, these findings should be ac- 

 cepted with reservation. It should be empha- 

 sized, however, that most of the estimates of the 



