Ruggerone et al.: Seasonal growth of Oncorhynchus nerka in relation to competition with O. gorbuscha 



359 



Pre-1977 



Post 1976 



Circuli pair 



Figure 3 



Percent change in scale growth of ocean age-3 sockeye salmon (O. nerka) 

 entering the ocean during even-numbered years compared to odd-numbered 

 years. Growth patterns represent ocean developmental periods prior to 1977 



( ) and after 1976 t ). Even-year smolts encountered odd-year 



pink salmon (O. gorbuscha) during their second year at sea (SW2), but they 

 encountered even-year pink salmon during their third year at sea (SW3). 

 Age 1.3 = 1 year in freshwater and 3 years in saltwater; age 2.3= 2 years 

 in freshwater and 3 years in saltwater. 



portions of SW1. including the annulus (circuli 18-22) 

 and immediately after peak growth (circuli 7 to 13) 

 (Figs. 2 and 3). 



SW1 growth of both even- and odd-year smolts tended 

 to be greater after the 1977 climate shift than prior 

 to this period, except for the last few circuli (Fig. 4). 

 The greatest difference in growth between these two 

 periods occurred immediately after entry into Bristol 



Bay (circuli 1-3) and during the last part of the SW1 

 growth period (circuli 13-19). This bimodal pattern of 

 growth between the two periods was somewhat con- 

 sistent among both stocks and freshwater age groups. 

 However, Kvichak age 2.3 salmon experienced especially 

 high early marine growth that was 17% greater, on 

 average, after 1976. Following peak scale growth in 

 spring, Egegik age 1.3 sockeye salmon experienced a 



