CONTENTS 



Page 



Introduction 1 



Part I. Adult sockeye salmon 3 



Numbers of spawners 3 



Age and length composition, sex ratio, and fecundity 4 



Relation of distribution on the spawning grounds to time of passage and abundance at 



the weir 7 



Success of spawning 9 



Rate of disappearance of carcasses after spawning 10 



Effects of bear predation 10 



Spawning behavior 11 



Mass movements of spawning sockeye salmon from Brooks Lake 17 



Lake beach spawning 17 



Part II. Juvenile sockeye salmon seaward migration 17 



Age and length of seaward migrants 18 



Length- weight relationship 21 



Daily and seasonal migration patterns 21 



Migration of juvenile salmon upstream 24 



Migratory behavior of juveniles as determined from observations 25 



Part III. Juvenile sockeye salmon lake residence 26 



Sampling gear 27 



Tow net 27 



Beach Seines 27 



Gill nets 27 



Seasonal and diurnal changes in vertical and horizontal distribution 32 



Length and weight by age class 32 



Food and its availability through summer growing season 35 



Parasites 39 



SCUBA 41 



Part IV. Limnology and its relation to sockeye salmon 43 



Plankton and its relation to juvenile sockeye salmon 43 



Zooplankton 43 



Phytoplankton 47 



Morphometry 49 



Bottom fauna 49 



Water quality 49 



Temperature 49 



Phosphorus 52 



Nitrogen 52 



Silica 54 



Turbidity 55 



Transparency 55 



Oxygen 56 



Hydrogen ion concentration (pH) 56 



Alkalinity and total hardness 56 



Primary productivity 59 



Summary of water quality analysis 60 



Temperatures of Brooks River and One Shot Creek 61 



Climatologlcal data 61 



Fluctuations In lake level 61 



Summary and conclusions 61 



Acknowledgments 63 



Literature cited 64 



