10 min. (minutes) for comparison of volumes 

 of plankton. 



The growth of periphyton was studied in 

 1956, 1957, and 1958, (Smoker, 1957, 1958, 

 I960). A different substrate was used each 

 year in an attempt to discover a technique 

 that would best facilitate handling and proc- 

 essing of the substrate and attached growths. 

 During 1956 standard glass nnicroscope slides 

 served as collecting bases; a series of slides 

 was strung together to cover the desired 

 range of depths. In 1957 the microscope slides 

 were replaced by a series of 15.2-cm. glass 

 plates. In 1958 solid glass rods about 1.2 m. 

 long and 12 mm. in diameter were tied end to 

 end and suspended from moored buoys. Each 

 rod had a total area of about 400 cm. 2. Each 

 year the substrate was left untouched for 60 days 

 in each lake. This period was selected because 

 tests run during 1956 showed that 60 days were 

 needed for the growth to be great enough to 

 measure. 



Throughout the 1961 field season, samples 

 of bottonn fauna were taken with a 15.2-cm. 2 

 Ekman dredge from shoal and deep areas in 

 Little Kitoi and Ruth Lakes. Shoal samples 

 were from about 1.2 m. depths; deep samples 

 were fronn the vicinity of maximunn depth in 

 each lake--26.8 m. in Little Kitoi Lake and 

 17.1 m. in Ruth Lake (table 1), The material 

 was preserved in formol alcohol (equal parts 

 of 5 percent Fornnalin and 70 percent ethyl 

 alcohol) and later was sorted. The organisms 

 were identified and counted, and the wet weight 

 of each sample was recorded (each sample 

 was blotted 1 min. and then weighed on an 

 analytical balance to the nearest milligram). 

 These data were transferred to IBM cards for 

 tabulation and summarization. 



GROWTH AND SURVIVAL OF SOCKEYE 



The results of this study encompass several 

 aspects of the life of sockeye in fresh water. 

 The timing of migrations and the apparent 

 effects of lake rehabilitation on survival. 



growth, and condition are considered in the 

 subsections that follow. 



Migration of Smolts 



The numbers of all species of downstream 

 migrants taken at the Little Kitoi Lake weir 

 from 1955 to 1963 are shown in table 3. Migra- 

 tions of sockeye, coho, and Dolly Varden 

 changed little, although they were slightly 

 higher in the later years of the study. Migra- 

 tions of sticklebacks and sculpins especially 

 decreased sharply throughout the study. This 

 reduction most probably is the result of instal- 

 lation of the weir; no sticklebacks or sculpins 

 have gained access to the lake from saltwater 

 since the weir was installed in 1955. The 

 salmonids have not been deterred by the weir 

 because they are able to gain access to an 

 upstream weir section by means of an alu- 

 minum Denil-type fish pass and are then 

 passed into the lake by hand. 



In general, the peak nnigration from Little 

 Kitoi Lake was 1 to 2 wk. (weeks) earlier for 

 2-annulus snnolts than for 1-annulus (table 4, 

 fig. 3). The peak nnigrations of 1- and 2- 

 annulus snnolts fronn Ruth Lake occurred about 

 the same time (table 4, fig. 4), The peak 

 migrations of 1- and 2-check smolts were 

 usually 1 or 2 wk. later from Ruth Lake than 

 from Little Kitoi Lake. The nnigrations from 

 Little Kitoi Lake tended to peak a few days 

 later as the years progressed, whereas those 

 fronn Ruth Lake remained fairly consistent 

 (table 4). The single year class of fry re- 

 leased in Midarm Lake departed as 1-check 

 smolts at the same time as the 1-check smolts 

 from Ruth Lake, and as 2-check smolts about 

 the sanne time as the 2-check snnolts fronn 

 Little Kitoi Lake (table 4). 



As shown in table 4 and figure 3, the down- 

 stream nnigration from Little Kitoi Lake in 

 1956 was unusual. The migration of 1-check 

 smolts in 1956 had two separate peaks. The 

 first and major one was almost a month earlier 

 than the average for the other years, whereas 

 the second peak was about 3 wk. later. In the 



Table 3. — Downstream migrants taken at Little Kitoi Lake weir,- 1955-63 



