Table 3. — tlumber of spavTning-rua s'iZ. Israpreys talcen in '•^i£f> ^^- 



traps in streams tributa:-"/ -'co_ north-western Lal-ce 



lEchigan (19ii?~- 1951} 



1/ The number of lampreys trapped in 1.9.45 is nc^t the complete laxi. into 

 ~ the streams trapping operations ware intermittent in that year. 



disappearance of the lake trout (a preferred prey species) froiT: the com- 

 mercial fisherj^. Maintenance of the population in Lake Huron at peak 

 abundance is attributed to the ability of the remaining fish stocks to 

 support, at least temporarily, the peak lamprey population. Those spe- 

 cies to which the lamprey has transferred its attentions are currently 

 suffering a severe decline. This same situation may apply to Lake Mich- 

 igan. 



Lake Superior . — The sea-lamprey population in Lake Superior continues 

 to increase, A recheck of streams, tributary to the eastern third of 

 Lake Superior,, in which evidence of spawning activity was noted in 1950 

 revealed considerable increase in spawning activity in the 1951 seasonj 

 several streams in which no activity was observed in 1950 contained evi- 

 dences of spaivning in 1951.2/ The niimber of spavming mLgrants taken in 

 at least one of the two experimental control structures operated in Lake 

 Superior tributaries indicates that ■y^rj effective (productive) spax-raing 

 runs are even now present in the most suitable tributaries! the progeny 



2/ A comprehensive report of a siorvey of the streains tributary to the 

 south shore of Lake Superior which was made in 1950 and 195l is now in 

 press. 



