(U) Relationshi p betT/een length and 



weight in spavining runs 



Both length and -weieht data Trere obtained for 2,180 sea lam- 

 preys collected during 19hl , 1,303 of ivhich were males and 877 

 females. Of the total, 1,^99 were talcen in Carp Greek and ^81 in 

 the Ocqueoc River, Average tveifhts by 0.2-inch length groups 

 were computed separately for the males and females of each of the 

 two runs. A comparison of corresponding sexes from both ivatersheds 

 indicated no si^iificant differences in the length-tveight relation- 

 ship. For this reason, the length and weight data for both runs 

 were combined, sexes separate (Appendix E, Table Ij.). For summaxy, 

 empirically determined averages of the males and females were plotted 

 separately on graphs, and curves were fitted to these points by in- 

 spection (Figures 21 and 22). 



In general, the weight of sea lampreys does not increase as 

 rapidly with length as does the weight of many higher fishes 

 (Beclcnan, 19U8). This is attributable to their more attenuate or 

 snake-liice body form? it is most evident in the male sea lampreys 

 "vrfiose weight remains more or less directly proportionate to the 

 length until a size of 19o5 to 20.0 inches is attained. Thereafter, 

 weight increases rather rapidly iirith length (Figure 21). 



Among the females, weight increases more noticeably with length 

 but the validity of this relationship is questionable due to the 

 profound effect of the developing ovary upon the total weight of 

 the female (Figure 22). 



The variation in weight at any given length is generally great 

 and increases with increase in length. Occasionally, the heaviest 

 specimen in a 0.2-inch length group exceeded twice the wei^t of 

 the lightest specimen in the same group. This is illustrated in 

 Figure 21 "ivhere the range in wei^t for each 0.2-inch length group 

 of males has been plotted. 



($) Migratory habits and behavior 



Sea lampreys swim with a whip-like, undulatory motion which 

 in its mechanics appears to be identical with that of the eel 

 ( Anguilla ) as described by Breder (1926) and termed by hims 

 "anguilliform locomotion." This is very similar to the familiar 

 movement of a snake traveling on the ground. 



Sea lampreys swim normally with the oral disc closed giving 

 the head a bullet-shaped conformity. The anteriorly cylindrical 

 and posteriorly compressed body, covered with copious amounts of 

 friction-reducing slime, adapt the species well to rapid locomotion. 

 These characteristics may be particularly useful when the animal 

 negotiates rapids and falls. During their upstream migration and 



-$9- 



