Table 11. — Size at maturity of pygmy whitefish collected 

 during the summer and fall from Brooks Lake and South 

 Bay, 1961-62 



1,200 



FECUNDITY 



The total number of maturing eggs in pygmy 

 whitefish ovaries were counted for 59 fish from 

 South Bay, 19 from Brooks Lake, and 7 from 

 North Arm. The number of eggs ranged 

 from 103 to 1,153 per female. Body length- 

 fecundity equations comjmted for each sample 

 showed some difference between areas. However, 

 a single equation was determined (fig. 12) by 

 grouping all 85 females, because there was no 

 overlap in the size range of females between 

 samples. 



The salient features of these fecundity data are 

 (1) that a broad range of fecundities exists in 

 different parts of the system and (2) that pygmy 

 whitefish from the Naknek system are consider- 

 ably more fecund than the same size fish from 

 Lake Superior. We transformed the total length- 

 fecundity relation given by Eschmeyer and Bailey 

 (1955) into a fork length-fecundity relation for 

 comparison with our data. A 120-mm. female 



PYGMY WHITEFISH OF SOUTHWEST ALASKA 

 795-353 O — 66 i 



2.9552*2.7513 1 09 L 



_L_ 



_L- 



70 



80 



90 100 110 120 

 FORK LENGTH (MM.) 



130 140 150 



Figure 12. — Length-fecundity relation of pygmy white- 

 fish from three areas of Naknek system. Equation 

 derived by combining data from the three areas. 



from Lake Superior (130 mm. total length) aver- 

 aged about 4-40 eggs, while the same size female, 

 from the Naknek system averaged about 580 eggs. 

 These differences in fecundity could be adaptive 

 responses of the various populations to different 

 environmental conditions that produce higher or 

 lower survival opportunities for the species 

 (Svardson, 1949; Nikolsky, 1963). 



SPAWNING SEASON AND BEHAVIOR 



Egg size in maturing females from South Bay 

 in 1962 increased markedly between late summer 

 and the fall spawning period. Egg diameters 

 that averaged 1.1 mm. in early August increased 

 to 2.4 mm. in ripe females in early November, 

 while ovary weight increased from 3.5 to 16.5 per- 

 cent of the total body weight (fig. 13). Egg size 

 and ovary weight relative to body weight in near 

 ripe fish from Lake Superior (Eschmeyer and 

 Bailey, 1955) were 2.0 mm. and 15 percent. 



Spawning of pygmy whitefish in Brooks Lake 

 and South Bay in 1962 and 1963 apparently oc- 

 curred between mid-November and mid-Decem- 

 ber. Mature, ripe males and females from South 

 Bay were collected near the mouth of Brooks 

 River on November 7 and 9, 1962. The water 

 temperature in South Bay on November 9, 1962, 

 was 3.9° C. Both eggs and sperm could easily be 

 extruded by exerting slight pressure on the abdo- 

 men, and females as well as males were tuberculate 

 over much of the body. The ventral fins of both 

 sexes were orange. Pygmy whitefish from 

 Brooks Lake on November 7, 1962, were not quite 



573 



