II 



O MATURING NONRIPE EGGS 

 • RtPE EGGS 



ClO 



•_ 



_l I I I L. 



_l I I I I I I I I l_ 



5 10 15 20 25 301 5 10 15 20 25 3015 10 15 20 25 301 5 10 15 20 25 30 

 AUGUST SEPTEMBER OCTOBER NOVEMBER 



Figure 13. — Seasonal maturation of pygmy whltefish col- 

 lected from South Bay, 1962. Average egg diameter 

 based on minimum of 10 eggs per female. N equals 

 number of females examined. 



as ripe as those from South Bay. Although ma- 

 ture fish taken in South Bay on October 29 and 

 November 5, 1063, were not quite ripe, three speci- 

 mens taken from Brooks River on the night of 

 November 6 apparently were, because sex products 

 could be readily extruded from them. 



The spawning period in the Naknek system 

 agrees with most other spawning information on 

 pygmy whitefish. The time of spawning in Lake 

 Superior (Eschmeyer and Bailey, 1955), Glacier 

 National Park, Mont. (Schullz, 1941), and four 

 British Columbia lakes (McCart, 1963) was be- 

 lieved to be in November or December. The 

 November-December spawing in the Naknek sys- 

 tem compares closely with the supposed time of 

 spawning in Lake Superior and Glacier National 

 Park, Mont. (Eschmeyer and Bailey, 1955; and 

 Schultz, 1941). Weisel and Dillon (1954) col- 

 lected sexually mature and spent pygmy whitefish 

 from Bull Lake between December 26 and Janu- 

 ary 12. Kendall (1917 and 1021) reported on six 

 pygmy whitefish collected from the Chignik River 

 system. Alaska, about November 1, 1912. These 

 fish (Kendall, 1921) were "mature individuals 

 ready to spawn," which agrees with the other 

 known spawning times of this species. 



Exceptions to the late fall and winter spawning 

 of pygmy whitefish have been noted. Kendall 

 (1921) reported thai sonic pygmy whitefish col- 

 lected on July 20, L909, and August 2, L912, from 

 the outlel of Lake Aleknagik were in breeding 



condition. Apparently the collector of one of 

 these samples reported that pygmy whitefish were 

 passing out of Lake Aleknagik in large numbers, 

 and Kendall interpreted this as a spawning run. 

 We question the validity of this interpretation and 

 doubt that a spawning migration was occurring as 

 early as July 20 or August 2, although individual 

 specimens might have seemed ready to spawn. 

 McCart. (1963) found a physiologically atypical 

 female in Cluculz Lake, British Columbia, on 

 July 15, 1962, which appeared to be ripe. We ex- 

 amined pygmy whitefish collected on July 13, 1963, 

 from Wood River just below the outlet of Lake 

 Aleknagik by Dr. R. L. Burgner of the Fisheries 

 Research Institute, University of Washington, and 

 found the condition of the gonads to be 3 or 4 

 months from full maturity. Two of the AVood 

 River females had average egg diameters of 1.0 

 mm., and the ovaries made up only 2.7 percent 

 of the body weight (fig. 13). Burgner (personal 

 communication) reports that large numbers of 

 pygmy whitefish can be seen throughout much of 

 the summer in Wood River below Lake Aleknagik. 

 These observations and Kendall's (1921) comments 

 on fish passing out of the lake could represent the 

 seasonal feeding movements of a lake population 

 similar to that observed during the summer in 

 South Bay and lower Brooks River. Pygmy white- 

 fish may spawn below Lake Aleknagik, but prob- 

 ably later than Kendall believed. 



Although specific details of spawning behavior 

 were not observed, we determined that pygmy 

 whitefish (in Brooks River at least) spawn only 

 at, night, as do mountain whitefish in Montana 

 (Brown, 1952). Routine underwater surveys in 

 early November in 1962 and 1963 revealed no 

 pygmy whitefish in Brooks River during daylight 

 hours, although large numbers of ripe or nearly 

 ripe fish were known to be in South Bay off the 

 river mouth. On a dive just after dusk on Novem- 

 ber 5, 1963, divers using underwater hand lamps 

 observed that a few large pygmy whitefish had 

 moved into lower Brooks River from South Bay. 

 Between 20 and 25 pygmy whitefish were observed 

 in the same area the following night about 3 hours 

 after darkness. These fish probably represented 

 the beginning of the spawning run in 1963. 



South Bay fish probably remain in the lake in the 

 vicinity of Brooks River until they reach full 

 maturity, when they move into the river at night 



574 



U.S. FISH AND WILDLIFE SERVICE 



