Results 



Mean laboratory growth rates were dependent 

 upon temperature and photoperiod (Table 1). 

 Comparison of mean daily growth rates, however, 

 is confounded by the effects of initial length. At 

 16L:8D, growth rate was positively correlated 

 with initial length at 10° C (r = 0.78) but nega- 

 tively correlated at both 15° and 20° C (r = -0.99 

 in both cases, Figure lA). At 12L:12D, growth rates 

 were negatively correlated with initial length at 

 10° C (r = -0.97) and at 15° C (r = -0.94) but 

 positively correlated with initial length at 20° C ( r 

 = 0.42, Figure IB). In the latter experiment, how- 

 ever, the length range was not as complete as in 

 the other experiments (Table 1). 



The relationship of growth to temperature and 

 initial length are more easily interpreted with the 

 multiple regression models. Regression coeffi- 



cients for the growth response models were all 

 significant with the exception of the length 

 squared term (Table 2). Effects of temperature 

 were similar at both photoperiods; growth in- 

 creased to some optimum temperature and then 

 declined (Figure 2A, B), as indicated by the nega- 

 tive value of the regression coefficient for tempera- 

 ture squared, 622 (Table 2). The apparent temper- 

 atures of optimum growth increased slightly with 

 length at 12L:12D but decreased with length at 

 16L:8D (Figure 2A, B). Initial length showed a 

 clear relationship with growth at 12L:12D (Figure 

 2B). At all temperatures, growth decreased with 

 increasing length; zero growth, observed in the 10° 

 C experiment at the largest sizes (Table 1), is pre- 

 dicted by the model at sizes >50 mm SL within the 

 range of temperatures studied. At 16L:8D, the 

 growth response to initial length is more complex. 

 At approximately 10.5° C the model predicts a 



Table L— Length-frequency distributions at the start and end of the growth experiments for 

 laboratory acclimated prejuvenile Sebastes diploproa at two photoperiods and three temperatures. 

 A^ = number offish in the experiment, X = mean standard length (millimeters), A = change in the 

 sum of lengths (millimeters) between start and end of each experiment, t = duration of the 

 experiment in days. 



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