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4.4.3 Grazers 61 



4.4.3.1 Sea Urchins and Sea Stars 61 



4.4.3.2 Molluscs 64 



4.4.3.3 Crustaceans 65 



4.4.4 Predators 66 



4.4.4.1 Sea Stars 66 



4.4.4.2 Molluscs 68 



4.4.4.3 Crustaceans 69 



4.5 Fish 69 



4.5.1 Introduction 69 



4.5.2 Canopy-midwater Species 70 



4.5.3 Bottom Species 73 



4.5.4 Other Species 75 



4.6 Birds and Mammals 76 



4.6.1 Birds 76 



4.6.1.1 Introduction 76 



4.6.1.2 Kelp Forests 76 



4.6.1.3 Drift Kelp 79 



4.6.1.4 Kelp Wrack 79 



4.6.2 Marine Mammals 80 



4.6.2.1 Introduction 80 



4.6.2.2 Sea Otter 80 



4.6.2.3 Cetaceans 82 



4.6.2.4 Pinnipeds 83 



4.6.2.5 Steller's Sea Cow 83 



4.7 Diseases 83 



4.7.1 Introduction 83 



4.7.2 Macroalgae 84 



4.7.3 Invertebrates 84 



4.7.4 Vertebrates 85 



CHAPTER 5 HYPOTHESES CONCERNING COMMUNITY STRUCTURE AND DYNAMICS . . 89 



5.1 Introduction 89 



5.2 Effects of Temperature 91 



5.3 Effects of Water Motion 93 



5.4 Other Abiotic Factors 93 



5.4.1 Depth Distribution 93 



5.4.2 Variability Within Depths 95 



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