FISHERY BULLETIN: VOL. 71, NO. 4 



300 

 CATCH 



Figure 11. — Relationships between mean length on 20 

 July and mean catch of sockeye salmon fry from 20 June- 

 19 July. A. Sockeye salmon fry: Y = 56.82 - 8.62 logioA' 

 (r = -0.86). B. Age I threespine stickleback: y' = 42.95 

 - 4.11 logioA* (r = -0.80). C. Char fry: Y = 38.93 - 

 2.56 logioA: (/- = -0.85). 



the three species were significantly correlated 

 but were most highly correlated between sock- 

 eye salmon fry and char fry (r = 0.990). Some 

 correlation was evident between length and (1) 

 date of ice breakup (small size — late date, 

 large size — early date) and (2) average water 

 temperature (small size — cold water, large 

 size — warm water) ; however the highest cor- 

 relations were between mean length and the 

 mean catch of sockeye salmon fry. The last re- 

 lationship appeared to be curvilinear, and re- 

 gressions of mean length on logarithm of mean 

 catch were significant at the 1% level (Figure 11). 

 Our main concern is with relationships in- 

 volving sockeye salmon fry and threespine 

 stickleback, as these are the most abundant 

 species in the littoral. An increasing abundance 

 of sockeye salmon fry results in a decreasing 

 growth of these fish as well as of associated 

 species in early summer. These data suggest a 

 limiting capacity in the lake for growth of indi- 



vidual fish in the populations during the early 

 summer but do not demonstrate a limiting capa- 

 city for the number offish. 



Annual variation in the relative abundance 

 of other species did not appear to affect the 

 growth of juvenile sockeye salmon; however, 

 since growth of these species was density de- 

 pendent (on juvenile sockeye salmon) and these 

 species share a common food supply (primarily 

 aquatic insects), there presumably was compe- 

 tition for food. If larger changes in the abun- 

 dance of other species occurred in Lake Alek- 

 nagik, there would probably be corresponding 

 changes in the growth of juvenile sockeye salm- 

 on. This question could best be examined by a 

 comparison of growth and abundance among 

 the lakes of the Wood River system. 



LITERATURE CITED 



BURGNER, R. L. 



1962. Sampling red salmon fry by lake trap in the 

 Wood River lakes, Alaska. Univ. Wash. Publ. 

 Fish., New Ser. 1:315-348. 

 Mathisen, O. a. 



1971. Escapement levels and productivity of the 

 Nushagak sockeye salmon run from 1908 to 1966. 

 Fish. Bull., U.S. 69:747-763. 



Nelson, M. O. 



1966. Food and distribution of Arctic char in Lake 

 Aleknagik, Alaska, during the summer of 1962. 

 M.S. Thesis. Univ. Washington, Seattle, 164 p. 



Parr, W. H.,JR. 



1972. Interactions between sockeye salmon and lake 

 resident fish in the Chignik Lakes, Alaska. M.S. 

 Thesis. Univ. Washington, Seattle, 103 p. 



Fella, J. J. 



1968. Distribution and growth of sockeye salmon 

 fry in Lake Aleknagik, Alaska, during the summer 

 of 1962. Univ. Wash. Publ. Fish., New Ser. 

 3:45-103. 

 Roger, P. B. 



197 1 . The ecology of two species of cottids in Iliamna 

 Lake, Alaska, and their relation to sockeye salmon. 

 M.S. Thesis. Univ. Washington, Seattle, 80 p. 

 Rogers, D. E. 



1964. Variability in measurement of length and 

 weight of juvenile sockeye salmon and threespine 

 stickleback. Univ. Wash. Fish. Res. Inst., Circ. 

 224, 34 p. 



1967. Estimation of pelagic fish populations in the 

 Wood River lakes, Alaska, from tow net catches 

 and echogram marks. Ph.D. Thesis. Univ. Wash- 

 ington, Seattle, 91 p. 



1968. A comparison of food of sockeye salmon fry 

 and threespine sticklebacks in the Wood River 



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