Green Creek, 12 miles east of Cheboygan is only about one tenth the 

 size of the Ocqueoc River and yet 89 tagged lampreys were captured in 

 this stream. In two even smaller streams, Elliott Creek (3 miles dis- 

 tant) and Little Black River ( 2 miles distant) 18 ana 55 tagged spec- 

 imans respectively were recovered (Table 9) • 



Significant contributions by the blocked Cheboygan River run were 

 made to other runs in streams UO miles distant alongshore in one direct- 

 ion and 25 miles in the other. The proportion of lampreys among the runs 

 of several streams studied that had their origin in the Cheboygan River 

 varied inversely with distance from that blockaded stream (Table 10). 

 For instance, the Little Black River, 2 miles west of Cheboygan, had 

 a run of 953 lampreys. On the basis of the aforementioned estimate 

 of ii0,000 lampreys as the size of the blocked Cheboygan River run, the 

 55 tagged lampreys recovered in this stream would indicate that 772 

 specimens or 8l percent of the total catch were diverted lampreys. 

 From similar computation it is found that in the Carp Lake River, 25 

 miles west of Cheboygan, 2 percent or 76 of the 3,821 individuals 

 taken there were from the Cheboygan River run. In an easterly direct- 

 ion, 95 percent or an estimated 253 of the lampreys taken in Elliott 

 Creek (3 miles distant) were diverted migrants. It is further indicated 

 that of the run in Green Creek, 12 miles east, 6I4 percent were origin- 

 ally from the same river. The Ocqueoc River, 30 miles east, attracted 

 an estimated 1,000 individuals from the diverted run. This figure was 

 only 5.3 percent of the total Ocqueoc River run. The two tagged lam- 

 preys caught in the Trout River weir and trap, h3 miles distant, indi- 

 cated that 1.6 percent or a probable 28 individuals had originally en- 

 tered the Cheboygan River. 



It is apparent from the results of this tagging experiment that 

 a significant portion of such a blocked run is diverted to other streams 

 in the immediate area which have accessible spawning grounds. Signif- 

 icant contributions by this blocked run were made to spawning runs in 

 streams 1|0 miles distant alongshore in one direction and 25 miles distant 

 in the other. It was also of interest to note that some sea lampreys 

 swam offshore, rather than following the shoreline in their search for 

 a spawning stream, crossed the Straits of Mackinaw, and appeared off 

 the shoreline and in streams of the Upper Peninsula of Michigan. 



It may be concluded from this experiment that trapping operations 

 to "siphon off" these large blocked runs may be of considerable bene- 

 ficial effect. Against such actions is the observation in Control Zone 

 H-l that these blocked and diverted migrants appearing in other streams 

 contributed only a portion to an already existing surplus of lampreys 

 entering these streams for which no spawning facilities were available. 



36 



