the lifts is more an indication of general activity than 

 choice of preferred temperatures; nevertheless, the 

 similarity in range of temperatures found in the two 

 studies is remarkable. Striped bass began entering 

 the fish lifts in late May when river temperatures 

 were about 17°C. During mid- to late May 1979-83, 

 the daily maximum temperatures in Long Island 

 Sound near the mouth of the river were much cooler 

 (12°-13°C, Millstone Laboratory, Northeast Utilities 

 Service Co., Hartford, CT). While we do not know 

 whether the striped bass overwinter in the lower 

 river or enter fresh from Long Island Sound each 

 spring, the movement of subadults from the cooler 

 waters of the Sound into the warmer river is con- 

 sistent with the thermal niche hypothesis of Cou- 

 tant (1985). The only data from the Connecticut 

 River that appears inconsistent with the hypothe- 

 sis of Coutant (1985) is the capture of nine subadults 

 in the lifts at Holyoke Dam in the fall of 1979 when 

 river temperatures were 7°-10°C. Although prey 

 abundance is high each fall at Holyoke Dam because 

 of the outmigration and death of many juvenile 

 American shad and blueback herring passed through 

 the turbines (Taylor and Kynard 1985), the temper- 

 atures when the striped bass entered the lifts were 

 much colder than preferred. Did the food abundance 

 cause some striped bass to remain in water tem- 

 perature that would otherwise be avoided? Because 

 no striped bass have been lifted in the fall since 1979, 

 we concluded that the event must be rare, whatever 

 the reasons. 



Radio Telemetry 



We tagged 63 striped bass with transmitters: 11 

 in 1981 and 52 in 1982. Three tags failed immedi- 

 ately after release (all in 1982); therefore, 60 fish 

 total were tracked. The study area was surveyed 

 from late June to late July during 13 d in 1981 and 

 47 d in 1982. 



Individual striped bass were tracked for periods 

 of 1-14 d: 35 were tracked for >1 d; and 25 were 

 tracked for >2 d. Fish were tracked for an average 

 of 4.3 d in 1981 (range: 1-14 d, N = 11) and 2.2 d 

 in 1982 (range: 1-12 d, A^ = 46). Tracks offish ended 

 because of tag regurgitation, tag failure, and move- 

 ment out of the study area. Operating tags were 

 regurgitated by 15 fish (4 in 1981, 11 in 1982) aver- 

 aging 3.6 d before regurgitation. There were four 

 known tag failures after an average of 3.5 d of obser- 

 vations. Tracking the remaining 41 fish ended after 

 they moved out of the study area or after undetected 

 tag failure. No striped bass were observed moving 

 upstream of the Cabon Station or into tributaries 



of the river. Surveys below Holyoke Dam located 

 seven tagged fish, one 75 km downstream of Hol- 

 yoke Dam near Hartford, CT. None of these fish 

 returned to Holyoke Dam and they may have con- 

 tinued moving downstream to the Long Island 

 Sound. Twenty additional fish were last observed 

 moving downstream toward Holyoke Dam, and we 

 expected that they also continued past the dam and, 

 possibly, to the Sound. Because there was no spillage 

 over the dam when many tagged fish returned 

 downstream to Holyoke Dam, they passed the dam 

 by entering one or more hydroelectric turbines. 



Only striped bass tagged in 1982 moved upstream; 

 the average upstream rate was 0.7 km/h (range: 

 0.30-1.2 km/h, A^ = 11). The mean rate of down- 

 stream movement was 1.9 km/h in 1981 (range: 

 1.0-3.2 km/h, N = 9); and 2.3 km/h in 1982 (range: 

 1.0-3.8 km/h, N = 21). Mean rates during the 2 years 

 did not differ significantly (Student's ^-test:P > 

 0.05). One striped bass, which was located nine times 

 during July 1982, traveled at least 143 km in the 

 study area during 14 d. 



Nine fish moving downstream in 1981 followed the 

 channel of the river; 61 of 68 locations were in the 

 channel at depths of 3-17 m. Although the actual 

 proportion of deep-channel habitat compared with 

 shoal habitat is unknown, there is much less chan- 

 nel than shoal area. Therefore, the preference for 

 the channel appears strong, as was also found in 

 telemetry studies of adult striped bass in Watts Bar 

 Reservoir, TN (Cheek et al. 1985). 



A total of 29 striped bass localized for periods of 

 90 min to 6 d in 13 different holding areas (Fig. 1). 

 (Two localized at more than one area; therefore, a 

 total of 33 such events were recorded.) Two fish 

 were rarely found simultaneously at the same site. 

 All holding areas, except the Route 202 Bridge site, 

 were located near a bank of the river. The Cabot 

 Station site accounted for 8 of the 33 localized 

 periods and for most of the longest periods, i.e., two 

 fish stayed at Cabot Station for 6 d each, one for 

 3 d, and three for 2 d. 



Fish activity in holding areas was highly variable. 

 Fish at Cabot Station moved in a stop-and-go man- 

 ner during the day and night, in shallow and in deep 

 water, and in the fast water of the power station 

 discharge and in the slackwater upstream of the sta- 

 tion. They appeared to be feeding in the discharge 

 of the hydroelectric station— we have observed 

 striped bass feeding in the discharge water of the 

 Hadley Falls Hydroelectric Station at Holyoke Dam. 

 Five fish were tracked at the outlet of the North- 

 ampton Oxbow (Fig. 1). All stayed in the main stem 

 within 0.5 km of the outlet, moved in a stop-and-go 



145 



