1 blackfish, 5 ninespine stickleback, and 9 

 threespine stickleback, 



32. Sockeye salmon fry were not success- 

 fully caught in gill nets because the smallest 

 mesh size was too large to hold them. 



33. Juvenile sockeye salmon were nearly 

 absent from midlake areas in early summer 

 but gradually adopted a pelagic life as the 

 season progressed, 



34. In midlake 79 percent of the sockeye 

 salmon were captured between the surface 

 and 15 feet, and only 21 percent from 15 to 

 45 feet, 



35. Increases in weight of lake-dwelling 

 juvenile sockeye salmonleveloff during August 

 and September when initial formation of an 

 annulus occurs. 



36. Of sockeye salmon caught in the lake 

 more were feeding on insects than on plankton. 



37. Incidence of empty stomachs increased 

 through the season. 



38. Four varieties of zooplankton and one of 

 insects made up the bulk of sockeye salmon 

 food in the lake. 



39. Sockeye salmon in the lake had no 

 serious parasite infestations. 



40. SCUBA is a practical method of observ- 

 ing fish in the natural aquatic environment 

 in Brooks Lake. 



41. Brooks Lake zooplankton and phyto- 

 plankton were well distributed at all depths 

 and stations through the season and, com- 

 pared with other North American lakes, were 

 relatively abundant. 



42. A large-scale contour map of Brooks 

 Lake was completed based on 57 transects 

 made with an echo sounder. 



43. Periodic chemical and physical meas- 

 urements were made of the following water 

 qualities from surface to bottom at three 

 stations: temperature, transparency, phos- 

 phorus, nitrogen, silica, turbidity, oxygen, pH, 

 and total hardness. Each of these was adequate 

 to support fish and was well distributed at all 

 depths through the summer. 



44. Primary productivity of Brooks Lake 

 was measured throughout the summer by the 

 Carbon^^ technique of Nielsen (1952) at 5-day 

 intervals at three stations from surface to bot- 

 tom; measurements in Naknek Lake were made 

 every 15 days for comparison. Primary pro- 

 ductivity was moderately low but extended to 

 a much greater depth in Brooks Lake than in 

 Naknek. Rate of production in Naknek Lake in 

 the surface region was greater than in Brooks, 

 but production in Brooks extended to a greater 

 depth. 



ACKNOWLEDGMENTS 



The enthusiasm and technical competence 

 of the six college students who assisted me at 

 Brooks Lake made possible the successful 

 accomplishment of program objectives. Each 

 assistant was responsible for one phase or 

 more of the program, and under my direction 

 each prepared an analysis and report when 

 the project was completed. Their reports are 

 the basis for this paper. Their individual 

 principal contributions and college or univer- 

 sity origins are as follows: W. L. Hartman, 

 Cornell University, contour map and spawning 

 behavior observations; C. R. Goldman, Uni- 



versity of Michigan, primary productivity; 

 W. H. Pogue, Humboldt State College, counts, 

 tagging, stream surveys, adult samples, and 

 climatological instruments; R. E. Painter, 

 University of Michigan, primary productivity, 

 spawning observations, and chemical water 

 analyses; J. A. Harbour, Eastern Washington 

 College, fingerling outmigration; F. P.Meyer, 

 Iowa State College, gill net sampling, food 

 studies, upstream migration of juveniles in 

 Brooks River, plankton, and fish parasites; 

 G. Y. Wong, University of Washington, chemi- 

 cal water analyses. 



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