FISHERY BULLETIN: VOL. 71, NO. 4 



LAKE 

 CHAUCKUKTUU. 



Figure 1. — The Wood River lake system and adjoining 

 river systems in the Nushagak District, Bristol Bay, Alaska. 



The primary objective in beach seine sam- 

 pling has been to obtain periodic estimates offish 

 length in early summer. The secondary objec- 

 tives have been ( 1) to estimate the annual relative 

 abundance and growth of fish species associated 

 with juvenile sockeye salmon to determine 

 the effect, if any, that they may have on survival 

 and growth of juvenile sockeye salmon and 

 (2) to determine the relationships among rela- 

 tive abundance of sockeye salmon fry, abundance 

 of parent spawners, and abundance of returning 

 adult sockeye salmon. The data and statistical 

 tests are detailed in Rogers (1972). The purpose 

 of this report is to examine the relationships 

 among annual estimates of the size and abun- 

 dance of fish and the physical parameters of the 

 environment during early summer. 



MATERIALS AND METHODS 



The seine used was 35 m in length and had a 

 midsection of 6-mm mesh, 7.6 m long and 3.7 m 

 deep. A 1.8-m bridle and a 17-m hauling rope 

 were attached to each end of the net. The seine 

 was set in a semicircle about 15 m from shore 

 and hauled by hand, usually by two men. 

 Catches consisting of less than 500 fish were 

 preserved in 10% Formalin.^ Larger catches 

 were successively divided in half until approxi- 

 mately between 200 and 500 fish remained. 

 These were preserved, and the fraction taken 

 was recorded. For each haul the date, time, 

 location, set direction, and surface water tem- 

 perature were noted. Other physical parameters 

 measured in connection with the beach seining 

 were the date of ice breakup, lake level, and 

 solar radiation. 



In 1962, beach seine hauls were made at 24 

 stations on Lake Aleknagik in eight time periods 

 between 20 June and 8 September. In 1963, 

 nine of the stations were sampled on 24 July 

 and 3 August. From 1964 through 1972, gener- 

 ally 10 stations (Figure 2) were sampled at five 

 weekly intervals between 22 June and 23 July 

 and once between 2 to 5 August. Seining was 

 conducted at the 10 stations between 0930 and 

 1600 h, seldom during rough water conditions, 

 i.e. when there were waves on shore. A descrip- 

 tion of the beach seine stations is given in 

 Rogers (1972). 



Between 1 and 7 days after collection, the 

 fish were enumerated and measured to the near- 

 est millimeter from tip of snout to end of middle 

 ray of the tail. In 1962 only juvenile sockeye 

 salmon and threespine stickleback, Gasterosteus 

 aculeatus Linnaeus were measured, whereas in 

 the remaining years fish of all species were 

 measured. Also, only 50 sockeye salmon fry 

 were measured in samples containing more than 

 75 sockeye salmon fry, and only 200 threespine 

 stickleback were measured in samples contain- 

 ing over 250 of this species. 



The length frequencies were plotted by species 

 and lake area (Figure 2) and for areas com- 

 bined. Partial age compositions were deter- 

 mined from the length frequencies, and mean 

 lengths were calculated for those age groups 



A detailed description of the gear and sam- 

 pling procedures is given by Waters (1969). 



3 Reference to trade names does not imply endorse- 

 ment by the National Marine Fisheries Service, NOAA. 



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