though the data from the two runs differed greatly 

 in time and space, the general migration pattern in 

 relation to river temperature was remarkably 

 similar. 



The behavior of the sea lampreys in the St. Johns 

 and Connecticut Rivers also appeared similar. In 

 1974, the first migrants were collected at 13°C at 

 the Mactaquac fish lift (Beamish and Potter 1975), 

 and from 1980 to 1983 the first migrants were 

 passed in the Holyoke fish lift at 10.5° -15.5°C. The 

 peak of the run was also similar— 17°-19°C in the 

 St. Johns River and 16°-21°C in the Connecticut 

 River. 



Mean length of the 45 sea lampreys tagged was 

 73.2 cm (range, 63.0-80.0 cm). Five were not re- 

 located either because the tag failed or the fish 

 moved downstream over the dam. No tagged sea 

 lamprey died during the study. The remaining 40 

 fish were followed for a total of 224 h during 24 d 

 (12 May-4 June; Fig. 3). Since sea lampreys mi- 

 grated upstream at Holyoke until 30 June 1982 (Fig. 

 2), for the most part we observed the movement of 

 early migrants. During the study, water tempera- 

 ture increased from 13° to 22 °C; river discharge 

 gradually decreased from 60.4 m 3 /s on 12 May to 

 50.9 m 3 /s on 31 May. Twenty sea lampreys moved 

 >23 km and 4 reached Cabot Station. Nineteen were 

 last located near the mouths of the Fort or Mill 

 Rivers or Russelville Brook (Fig. 1). Spawning of 

 tagged fish was verified in the tributaries— an in- 

 dication that normal behavior resumed after the sea 

 lampreys were tagged. 



Sea lampreys moved upstream at ground speeds 

 of 0.1-3.5 km/h. The daily mean rate of movement 

 including rest periods was 1.01 km/h ± 0.75 (mean 



±SD; range, 0.1-2.7 km/h; N = 40) or 0.4 body 

 length/s. The mean rate, excluding rest periods, was 

 1.51 km/h ± 0.53 (range, 0.1-3.5 km/h; N = 39) or 

 0.6 body length/s. Early migrants moved a mean of 

 0.1-1.2 km/h; and three migrants that were observed 

 during the peak passage at the fish lift on 2 June 

 had the fastest mean daily rate of 2 km/h (Fig. 

 3). 



Among landlocked sea lampreys, early migrants 

 have a slower rate of movement than peak migrants 

 because they rest more (Applegate 1950; Skidmore 

 1959; Larsen 1980). Our observations during the 

 peak period after 30 June did not indicate a sus- 

 tained increase in the rate of movement (Fig. 3). 

 Because we only observed a few peak migrants, 

 additional study is necessary to compare the rates 

 of movement between early and peak migrants. 



The movement rates of sea lampreys in the Con- 

 necticut River were the highest reported for the 

 species. Landlocked sea lampreys moved at much 

 lower rates of 0.02-0.21 km/h (Applegate and Smith 

 1950; Skidmore 1959; Wigley 1959). Beamish (1974) 

 found a maximum swimming speed of 1.08 km/h (30 

 cm/s) for landlocked adults in the laboratory. Using 

 the energetics of adult sea-run sea lampreys dur- 

 ing a 35-d upstream move into the fish lift at Mac- 

 taquac Dam on the St. John River, Beamish (1979) 

 estimated the rate to be 0.23 km/h for males and 

 0.26 km/h for females, or 0.1 body length/s for both. 

 This rate was similar to that of the landlocked form. 

 Because the sea-run adults are much larger than 

 landlocked adults, they should swim faster. Our 

 results suggest that the 0.2 km/h rate which was 

 estimated for the St. John River adults may be in- 

 correct, possibly because the fish were delayed 



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Figure 3.— Daily mean rates of movement of radio-tagged sea lampreys (open circles). (Vertical lines 

 show standard errors; numbers of lampreys monitored are shown above each mean.) 



752 



