Ilean dally v;-ater tenporatiircs in the Ocqueoc River in 1?I|9 

 varied froiii 3h*S degrees F. to 30.0 decrees F. during the period 

 of •.Teir operation (Firiire 13). ITo migrants vrere talcen in the vreir- 

 trapc ■'jjitil April 23 although- T.-ator tenpGratures or UO degrees F. 

 to 50 degrees F. had prevailed during nearly all of the 17 pre- 

 ceding days. Iligrants irere present, horraver, belor; the rreir. This 

 delaj^ed movement during ivater tenperatures satisfactor;.'" for nigration 

 is attribttted to the bloclcing action of the v;eir structure in the 

 river. Earlj- nigrants are apparentlj^ more easily'' disco-uraged fror. 

 continuing their journey tl:an those nigrating later v-hcn lii^aor 

 temperatures prevail. On llay 30^ nean daily water temperatures rose, 

 and renained above 50 degrees F. Albv.ost ir'nedic.tel;'' an upctrean 

 r;iovei.-ent of great intensity began (Figure 13). Presur^ably, this 

 sudden, greet noverrient was composed of fresh mig-rants frori the laJce 

 and the accumulation of blockaded indi^dduals that had been seen 

 beloT.' the weir. The run ".vas continuous in chai'acter, thereafter, 

 ujitil July 3- Two general recessions in v.'ater tenpcratuxes and 

 migratory activitj' occurred corresponding to those v^iich occurred 

 in Carp Creel: in the same year (Hay 9-16, l!ay 26-2?). These data 

 ag-ree with the obser^-ations of Shettor (1?!;!?) for the l^U^ sea Ian- 

 prey run in the Ocqueoc Fdver for r,hich he noted that the greatest 

 migratory activity occurred at water tenperatures of $1 degrees F. 

 or liigher. The effect of high water temperatures upon the Ocqueoc 

 Fdver run was less pronounced than tho.t at Carp Creek. On June U 

 and 5 the mean daily vrater tenpcratui^e rose above 65 degrees F. 

 and migrator;'" activity decreased. Cooling of -the vrater in the 

 succeeding five days brought a brief increase in migrator^'' activity. 

 On June 11, water tem.peratures rose again, and rem.ained above 65 

 degrees F., and upstream movement once more declined. 



It should be noted that the erratic character of the sea lam- 

 prey run in Carp Creek is probably characteristic of most small sea 

 lamprey spavjning streams T:here temperatures respond rapidly to 

 climatic changes. Data presented by Shetter for the Ocqueoc River 

 run in 19h$ and those collected by the vn-iter in 19h7 and 19h9 

 (Figure 18 j Appendix C) for the same stream indicate that in a 

 larger streai-i rdth more stable temperatures the sea lar.iprey run 

 has a correspondingly more continuous character. 



Certain inexplicable declines in the number of nigrants enter- 

 ing the Carp Creek trap were not alrrays preceded or accompanied by 

 a proportionately rapid drop in water temperature, and sometimes 

 occurred on a slightly rising or stable temperatui-e. This fact seems 

 to be related to the effect of certain onshore winds upon the vrater 

 discharged from, the creek into the zone of wave action along the Ham- 

 mond Bay shore. The creek water was alv.-ays identifiable until thor- 

 oughly diffused into that of the bay by its distinctive brorm color 

 and usually higher tenperatures. Under such conditions I could 

 ordinaril;y wade to a point beyond the band of deflected creek water 

 and seldom be standing at a depth greater than tvro feet. 



It appears that seroially matm^e sea lampreys vihen seeking a 

 tributarj' stream in which to spavm are attracted into that stream, 



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