Turners Falls Dam 

 km 198 



Figure 1.— Section of the Connecticut River from river km 140 to 198, showing the loca- 

 tions of the Holyoke and Turners Falls Dams, the release site for radio-tagged sea lampreys 

 at Brunelle's Marina, and the major spawning tributaries between the two dams. 



tire run each year except in 1981 when sea lampreys 

 were present in the first lifts of the year (the lifts 

 began operating on 29 or 30 April of each year). Dur- 

 ing the peak 7 d, the temperature ranges, and year 

 in parentheses, were 16°-19°C (1980), 17°-19°C 

 (1981), 16°-17°C (1982), and 17°-21°C (1983). 

 Movement into the fish lift ceased at 24°C in 1983 

 and at 21°-22°C in the other years (Fig. 2). 



Information on the maximum daily temperature 

 during the migration of landlocked sea lampreys in 

 a large river comes from the Ocqueoc River (Lake 

 Huron drainage) which for some years supported an 

 annual run of 25,000-40,000 (Applegate 1950; Apple- 

 gate and Smith 1950). The temperatures, and date 

 in parentheses, when the first sea lampreys entered 

 a weir near the mouth of the river were 10°C (27 

 April 1949) and 6°C (11 May 1950); and the run 



peaked at 14°-17°C (first week of May 1949) and 

 18° -20°C (third week of May 1950). Most movement 

 at the weir ceased at 21 °C (about 11 July), but dur- 

 ing both years one or two sea lampreys per day con- 

 tinued to enter the weir throughout the summer at 

 22°-26°C. 



The temperature regimes in the Ocqueoc and Con- 

 necticut Rivers during the peak and at the end of 

 the principal migration were in general agreement. 

 Runs peaked at 14° -20°C in the Ocqueoc River and 

 16° -21 °C in the Connecticut River; most of the run 

 ceased at 21 °C in the Ocqueoc River and at 

 21°-24°C in the Connecticut River. The migrations 

 differed because a few adults in the Ocqueoc River 

 continued to migrate throughout the summer, 

 whereas none were captured after 25 June during 

 3 yr in the Connecticut River. Therefore, even 



750 



