to the beginning of iveir operations. Only a snail nunber of lam- 

 preys (h9 individtials ) entered the trap between April 9 and April 19 

 (Figure 1?). Thereafter, the run increased slov.-lj'- until April 23 

 and on that date began to rise abruptly to maxiriun activity. Lost 

 migrants (87.8 percent) entered the creek dui'ing the 39-da;' period 

 "vsiiich follorred (to June 5)» As in previous years, the period of 

 major upstream movement was roughly cleft by a cold spell. In 

 19^9, this interruption of tlao run occurred during Kay 9-l6. 



Trap catches in excess of 100 sea lampreys during a 2l|.-hoiir 

 period occurred on seven different occasions. The greatest move- 

 ments in this season "vvere on the nights of Hay 1-2 and IJay 6-7. 

 On both occasions, llil sea lampreys vrare talcen. 



From June 6 to 30, trap catches were small and movement up- 

 strean ivas erratic although continuous. The last migrant to enter 

 the creek was taken on July 6. 



The total run in 1914-9 "vvas composed of 2,763 sea lampreys. 



The spring of 19h9 ims somerjhat earlier than and equally as 

 vrarm as that in 19l|.8. The sea lamprey run displayed character- 

 istics very similar to the run occurring in 19U3. Sudden movements 

 of large numbers of migrants occurred during hot, humid periods 

 although v/ithout quite the intensity of this phenomenon in 19h3. 

 It was like7d.se noted in the field that these periods of hot weather 

 in I9J-I.9 were not as intense as those occurring in 19U3 (refer to 

 air temperature and weather data in Appendiic C). 



Ocqueoc River , 19l;7 ' — Data collected for the Ocqueoc River run 

 in I9I4.7 were concerned almost entirely vd-th the arrival, e:ctent of 

 activity, and disappearance of the Ismpreys on their spaiming 

 grounds. Conclusions as to the time limits and pealrs of migrator;' 

 activity, as they might be measiired hj a weir and trap near the 

 river's mouth, are based entirely on field obpervations and a con- 

 sideration of r.u.grator;'- activity at the Ocqueoc falls, 8.8 miles 

 upstream from the mouth of the river. 



It was reported to me by Vt, Snos Erege of Ocqueoc, Fdchigan, 

 that on or about April 10, 19U7j he saw "several" sea lair.preys off 

 the mouth of the Ocqueoc River while he was prospecting for the 

 beginning of the smelt run. Data presented by Shetter (I9h9) for 

 the 191d sea lamprey run show daily trap catches of no or solitary 

 sea lampreys for the period April 22 (first da;r of trap operations) 

 to April 28, during which time, the average daily water temperature 

 varied from I4.2 degrees 7. to Uit degrees ?. In 19h7 , mean daily 

 water temperatvu-es in the Ocqueoc River remained below hO degTees F. 

 until April 21 (Appendix C). After consideration of these data and 

 those presented in this report for Carp Creek for the period April 

 li;-21, I believe that little or no upstream migration occvirred until 

 on, or about, April 20, 19U7. 



The greatest concentrations of sea lampreys at and on the Oc- 

 queoc falls were present during the period June Ii-17. Water temper- 

 atures at the falls during this period varied from $6 degrees 



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