Mortensen et a\ Growth of Oncorhynchus gorbuscha in relation to marine water temperature, secondary production, and survival 329 



o 



6 



4 

 2 

 

 -2 . 



1986 



b = 342 

 P<0.0\ 



■o 

 5 



15 -2 



1987 



b = 327 

 P<0.0\ 



1988 



b = 0.250 

 P<0.01 



1989 



11 



13 



Temperature (°C) 



Figure 7 



Residuals between the observed growth rate of tagged juvenile pink salmon 

 and expected growth rate of juvenile pink salmon fed excess ration. Year shown 

 refers to recoverv vear. 



Interannual growth of tagged pink salmon 



The growth rates of juvenile pink salmon from indi- 

 vidual release groups varied substantially between 

 years (Table 1). All release groups of juvenile pink 

 salmon in recovery year 1986 (1985 BY) grew sig- 

 nificantly slower than those of juveniles in subse- 

 quent years. In 1987 ( 1986 BY) and 1988 ( 1987 BY), 

 the only years when tagged juveniles from the 1 

 April group were recovered, growth was not signifi- 

 cantly different. Similarly the growth of juveniles 

 from the 7 April groups were not significantly differ- 

 ent between years. Juvenile pink salmon from the 15 

 April and 22 April releases gi'ew significantly slower 

 in 1987(1986 BY) than in 1988 (1987 BY) or 1989 

 (1988 BY), by nearly l^c. Growth was significantly 



slower (about O.S'^ bwd) for the 22 April release 

 group in 1989 (1988 BY) than in 1988 (1987 BY). 

 The juveniles from the 29 April release grew signifi- 

 cantly faster (0.3<7f bwd) m 1988 (1987 BY) than in 

 1989 (1988 BY). 



Growth in relation to water 

 temperature and prey biomass 



Water temperature was the only environmental 

 parameter measured that was significantly corre- 

 lated with growth rate over all years (Table 3). 

 Both simple and partial correlations were significant 

 (<0.05) in each year for water temperature, and in 

 every year except 1988, temperature explained the 

 most variation in the parameters tested. 



