FISHERY BULLETIN: VOL. 71, NO. 4 

 Table 7. — Regression parameters for In mean catch on coded date (23 June= 1), 1962, 1964 through 1972. 



'Calculated from geometric mean catches except age 



^Calculated from geometric mean catches in lake area A only 

 •'The regression parameter ti is th 

 of decline in catch. 



e natural logarithm of the calculated catch on 22 June, and the parameter h is the instantaneous rate 



(area A) than in the middle section and the 

 outlet with the exception of station 7S. They 

 were never caught at station 8N. Their distri- 

 bution in early summer probably reflected the 

 distribution of parent spawners in the previous 

 fall. 



Catches of char fry tended to increase during 

 the first four periods of sampling and then to 

 decrease in the last two periods. They may not 

 have been as available to the beach seine as 

 early in the spring as sockeye salmon fry be- 

 cause of later emergence from the spawning 

 grounds. 



Annual Variation in Abundance 



The geometric mean of the annual mean 

 catches in each area during 20 June-19 July was 

 considered the best estimate of the relative abun- 

 dance in Lake Aleknagik during the period of 

 the summer when sockeye salmon fry were con- 

 centrated inshore. On the average, juvenile 

 sockeye salmon were the most abundant species 

 in the littoral and also exhibited the greatest 



annual absolute as well as relative variation 

 (coefficient of variation) over the years. Signif- 

 icant differences were detected in the mean 

 catches by year for all species, but the relative 

 annual variations in catches for the next two 

 most abundant species (threespine stickleback 

 and slimy sculpin) were low compared to that 

 of juvenile sockeye salmon. 



Linear correlation coefficients were calculated 

 for the purpose of examining relationships 

 among annual estimates of abundance, apparent 

 mortality rates, and selected physical param- 

 eters. A total of 84 pairs of variables was ex- 

 amined for correlation and statistically signifi- 

 cant correlations at the 5% level were found 

 among 38 pairs. Obviously some caution is 

 needed in the biological interpretation of these 

 data. It is expected that 5% of the tests would 

 reject the null hypothesis that they are inde- 

 pendent. Some partial correlation coefficients 

 were examined; however, none were found sta- 

 tistically significant. The notable results of the 

 correlation analysis were: (1) significant posi- 

 tive correlations between water temperature 

 and apparent mortality rate for threespine 



1070 



