Table 23. — Parent escapement ofsockeye salmoii, as numbers 

 per square kilometer of lake, average catch of age progeny 

 per standard tow, and average length of age progeny in Black 

 andChignik Lakes, 1960-61 



existent differences in growth rates between 

 seasons. 



For Karluk Lake, both the average catches of 

 juvenile sockeye salmon in tow nets (tables 17 

 and 18) and the average lengths for each age 

 group (adjusted to September 1) were among 

 the lowest recorded in this study (tables 19, 20, 

 21). 



Associated Species 



Several species of fish are captured frequently 

 with juvenile sockeye salmon in the tow nets. 

 The species and abundance vary from system to 

 system. The most common in order of general 

 abundance are threespine stickleback, ninespine 

 stickleback, pond smelt, and pygmy whitefish. 



The threespine stickleback is the most abun- 

 dant species associated with young sockeye salm- 

 on in the Wood, Kvichak, Naknek, Chignik, and 

 Karluk systems (table 24) . Both species tend to 

 concentrate near shore in the spring and spread 

 toward the pelagic area of the lake as the season 

 advances. Similarities in the food habits of these 

 two species have been well established (Rogers, 

 1961). 



Wood system. — The average abundance of 

 threespine sticklebacks in tow net catches in the 

 Wood system varied in 1958-62 (table 24) almost 

 as much as, but seemingly independently of, that 

 of juvenile sockeye salmon. In some years the 

 biomass of the sticklebacks, as indicated by 

 abundance in tow net catches, has approached or 

 exceeded that of the juvenile salmon. 



The average rate of growth of threespine 

 sticklebacks varies from year to year and usu- 

 ally in the same direction as that of the juvenile 

 sockeye salmon (fig. 8). The slowest growth of 

 threespine sticklebacks (and of juvenile sock- 

 eye) generally is in years of greatest abundance 



Table 24. — Weighted mean catch of sticklebacks per standard 

 tow (stirface ayid deep tows combined), August 16 to Septem- 

 ber 15 in lakes of the Wood, Kvichak, and Chignik systems. 

 195S-62 



Fish per tow 

 Species, system, and lake 



1958 1959 1960 1961 1962 



Number Number Number Number Number 

 Threespine sticklebacks 



Wood system 



Lake Aleknagik 81-4 310 2 85.2 62 4 188.0 



LakeNerka 51.5 53 4 26 4 24 30 2 



Lake Beverley 133.0 51.2 53 7 22 3 



Lake Kulik 285.6 219 14.8 13 2 14,1 



Little Togiak Lake 113 4 106 3 25.2 510 65 6 



Kvichak system 



Iliamna Lake 27.8 



Lake Clark 



Chignik system 



Chignik Lake 3 8 



14.1 '5.0 

 Black Lake 170 3 



' 196 4 1 162 4 

 Ninespine sticklebacks 

 Chignik system 



Chignik Lake 7.2 



16 6 1 7.0 



Black Lake 32.2 



17.2 128.9 



1 Surface tows only. 



46 

 45 

 44 

 43 

 42 

 41 

 40 

 39 

 38 

 37 

 



 lake aleknagik 

 ♦lake NERKA 

 A LAKE BEVERLEY 

 • lake KULIK 



Lf-J- 



Y = 24.58-(-0.3l2X 



_l I I I I L. 



45 50 55 60 



MEAN LENGTH OF AGE SOCKEYE SALMON (MM : 



Figure 8. — Relation between mean length of age I three- 

 spine sticklebacks and mean length of age sockeye 

 salmon taken in tow nets each year, 1958-62, in each 

 of four lakes of the Wood system. The mean lengths 

 of both species have been weighted and adjusted to 

 September 1. 



436 



U.S. FISH AND WILDLIFE SERVICE 



