presmaably during all of the acjialt phase of their life cycle tl:'.ey 

 c.re^ on occasion^ Tsiy fast p-jviramers. '^l/hen traversing areas of 

 piTift Trater, and vrfoen rLUTnotinting obstacles such as dams or 

 naturai'L falls, or when frightened, (presumably also iThen over- 

 taking their prey) the;?" are capable of amazing spurts of speed, 

 Eoivever, these sudden spixr-ts undoubtedly represent the tenriinal 

 swimning velocity of the species and it seems un3JJcely that they 

 could sustain such speeds for any appreciable distance. 



When not taxed to their utmost by circumstances, the avrlxi- 

 ming habits (in migration) of the sea lamprey differ materially 

 from those of other fishes. They seldom rest in midr/atsr by •.Tiairi- 

 taining their position and balance in the current through contl'.iUxil 

 movement. Rather, n*ien not deliberately moving upstream.^ ohaugirig 

 position;, or seeking their- way around or over an obstacle, they 

 (O-ing by their mouths to a rock or log or any available soli.d 

 object. This behavior fjas noted even under conditions of little 

 c:: no current and among individuals resting in static -vater. 



Related to th,eir capacity for sudden bursts of speed is their 

 ability to work their waj'- over many natural falls and man-made 

 dams of low or ir-regular construction. Surmounting such obstacles 

 is nox. accomplished by spectacular leaps as among the saljnons... but 

 by throTdng themHel-ria upiiTjrr^l snd forward, in short, "■.vriggling 

 thrasts and securing each gain by attaching themselves firmly in a 

 new position by their oral dieisi.' 'Za.dh gain is followed by a seem- 

 ingly long period of reut before aitother attempt is made to move 

 farther. In this fashicxi;, they progress slowly up and over the 

 faces of falls, fcllovdng crevices and fissures ivhich offer the 

 least resistance by current or vertical surface. Air chambers be- 

 hind the falling water are traversed by the sea lampreys with no 

 apparent difficulty. I have seen masses of them in such locations 

 that were wet only by spray or occasional turbulent surges. Vifhere 

 falls and low dams offer vertical surfaces to be negotiated, it 7/as 

 noted that the sheer mass of the accumulation of migrating i]-«.divi- 

 duals occasionally forced the topmost indii/iduals to a position 

 •.•iiiiore the barrier could be claared in a single thrust. Yiass action 

 in. these instances ensures that at least some indiTidixals maj;- gain 

 the spaiming gi'ounds. T!tae precedj^ng observations were made in the 

 faLls of the Ocquecc Ri.vei' and at several low dans on that ■j-r.Me.r 

 where it was possible to trace the routes of the lampreys ov'^jr these 

 obstructions by exploring the face of the falls by hand. 



Observations en the Ccqueoc and at several high daiiis, such as 

 those on the Cheboygan ar^d. lianistique rivers ; indicate that s :'.?. 

 la'-apreys can seldom "jump" vertically more than two feet althvn.gh they 

 have been occasionally observed leaping as much as fovir feet ±n a 

 forivard and slightly upward direction at the base of a natioral fiJls. 

 It is of interest to note that they can, and occasionally dr\, ".e;ip 

 o-'it of a 10-gallor milk can containing about 12 inches of ivatei.'. 



62 - 



