Table 19. --Rate of catch in fyke nets and mean size of age sockeye salmon migrating down 

 Coville and Grosvenor Rivers during dark and light periods 1 between July and September 1961-62. 



1 Average sunrise and sunset times were determined for each semimonthly period from pyrheli- 

 ograph records from Coville Lake outlet. Dark = sunset to sunrise when pyrheliograph reading was 

 0. Light = sunrise to sunset. 



2 In 1961, a 1-m-square fyke net was fished from steel posts driven into stream bottom. In 

 1962, a 1.2-m- square fyke net was fished from a cable strung across the stream; the wings were 

 spread to 1.3m. 



3 A 1.2-m- square fyke net was fished from a cable strung across the stream; the wings were 

 spread to 1.8 m. 



4 0ne fishing period of 4 hours duration produced an exceptional catch of 1,500 juvenile 

 sockeye salmon. 



Lake, but were not concentrated near the river as at 

 Grosvenor Lake. The accumulation of fish near the 

 outlet of Grosvenor Lake probably resulted from their 

 reluctance to migrate down the river during daylight. 

 Juvenile sockeye salmon have been studied in sev- 

 eral multibasin systems similar to the Naknek system 

 and oceanward interlake migrations of significant 

 numbers of age sockeye salmon during the summer 

 are apparently rare. The several basins of the Babine 

 River system have markedly dissimilar densities of fry 

 early in the summer as the result of the unequal dis- 

 tribution of spawning adults (much as in the Naknek 

 system). Unlike the fry of the Naknek system, the fry 

 of the Babine system do not disperse over the lakes 

 during summer (Johnson. 1958). (The greatest number 

 of spawners per unit lake area is in the most upsystem 

 lake of the Naknek system, but in the lower end of the 

 Babine system.) In the Wood River system there is a 

 minor migration of fry from small lakes to a larger lake 

 (Burgner, 1962). In the Chignik River system there is 

 little downsystem movement of age fry between 

 lakes, but here (similar to the Babine system) the 



downsystem lake usually has the greater density of 

 spawners. There is a migration of fry from the lower 

 lake (Chignik Lake) to the lagoon-like estuary (Burg- 

 ner et al., 1969). A recent study of growth patterns on 

 scales of adult sockeye salmon from the Chignik sys- 

 tem indicates that age fish did migrate to a downsys- 

 tem lake in 1956 9 (Narver, 1968). 



A migration unusual because of its direction has 

 been reported for Owikeno Lake, British Columbia. 

 Ruggles (1966) found a movement of age sockeye 

 salmon from one lake basin to another away from the 

 direction of the outlet to the ocean. The time of the 

 migration and relative density offish in the two basins 

 before and after the migration were not reported. Dur- 

 ing the winter another migration occurred, but this 

 time it was oceanward. 



"At 1700 on 30 July 1962 the speed of movement was estimated 

 for 10 schools of age sockeye salmon moving downstream at the 

 outlet of Coville Lake. The current speed, gaged by observing a 

 floating wood chip, was about 0.2 feet per second (fps). The speed of 

 the schools averaged about 1.9 fps, indicating a swimming speed 

 downstream of about 1.7 fps. 



30 



