COYER: INVERTEBRATE ASSEMBLAGE WITH CIANT KELP 



sponsible for the increased abundances in the lower 

 zones during this period. 



Fluctuations in the population size of several 

 species may have been associated with changes in 

 kelp biomass, particularly the general decline of kelp 

 biomass beginning in fall 1976. The canopy mysid 

 probably attains its greatest population size during 

 winter; however, the canopy was markedly reduced in 

 area by winter 1976-77 and the mysid was rare. 

 Copepods and gammarids displayed decreased 

 canopy abundances during late 1976, and in the 

 lower zones, abundances of the gammarid M. litotes 

 began to decline as kelp biomass was reduced. As the 

 canopy mysid andM. litotes were major components 

 of the general invertebrate peak observed during 

 winter 1975-76, their reduced abundances in late 

 1976 undoubtedly were a major reason for the 

 absence of a general invertebrate peak in late 

 1976. 



Reduction in kelp biomass, however, did not affect 

 H. clorki. Even though the shrimp was most 

 numerous in the canopy, its abundance in the 

 reduced canopy of late 1976 was similar to levels 

 recorded in the larger canopy of late 1975. 



Although the amount of kelp biomass ultimately 

 must determine the abundance and occurrence of 

 kelp-associated invertebrates, the importance of 

 proximal factors remains to be determined. Proximal 

 factors may be particularly important in many areas 

 of southern California, where the kelp forests are 

 characterized by relatively long-term cycles of loss 

 and renewal (Rosenthal et al. 1974). In such con- 

 ditions of relative biomass constancy, abundances of 

 some species may not be correlated with seasonal 

 changes (i.e., temperature, day length, nutrients, 

 etc.). Additional research is necessary to determine 

 the importance of proximal factors such as kelp 

 quality (healthy vs. decomposing), inter- and intra- 

 specific competition for space and food, and preda- 

 tion by fishes and/or motile invertebrates, in 

 determining the abundance and occurrence of kelp- 

 associated invertebrates. 



ACKNOWLEDGMENTS 



The manuscript was adopted from a portion of a 

 doctoral dissertation completed at the University of 

 Southern California. I thank my committee, chaired 

 by J.N. Kremer, and am grateful to R. L. Zimmerand 

 R. R. Given for their support and cooperation at the 

 Catalina Marine Science Center. The substantial 

 field assistance of J. R. Chess, J. F. Pilger, C. S. 

 Shoemaker, and T. E. Audesirk is sincerely appre- 

 ciated. Special thanks to D. Cadien, J. R. Chess, G. 



Kramer, B. Myers, J. Soo-Hoo, J. Word, and R. C. 

 Zimmerman for assistance with species identifica- 

 tion and to G. S. Hageman for help in sorting samples. 

 The valuable suggestions of R. J. Schmitt, R. F. 

 Ambrose, and two anonymous reviewers improved 

 earlier drafts of the manuscript. 



The research was supported in part by the NOAA 

 Office of Sea Grant under Grant No. USDC 04-158- 

 44881 to the University of Southern California and 

 by Sea Grant Traineeships. 



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