632 



Fishery Bulletin 92(3). 1994 



able to bottom trawling off Oregon and Washington, 

 a resource manager may elect to base management 

 decisions on the union of these two because of the 

 difficulty in monitoring the often discarded sharp- 

 chin-redstripe-rosethorn rockfish assemblage. How- 

 ever, in managing the rockfish community as a whole, 

 this assemblage needs to be considered along with other 

 minor species commonly caught in the fishery. 



Our understanding of the associations among rock- 

 fish has improved greatly. Assemblage studies, com- 

 bined with studies on life history, distribution, and 

 abundance, continue to assist in refining current re- 

 source management policies and may eventually lead 

 to a more multispecies management approach. Such 

 an approach will address the impact on the ecosys- 

 tem when operations target on a single species, such 

 as yellowtail rockfish, with little regard to the ef- 

 fects on other species, particularly those of lower eco- 

 nomic value. Likewise, it will also address the con- 

 tinued removal of a species like yellowtail rockfish 

 due to incidental catch when operations target on 

 another species. 



Acknowledgments 



Fisheries biologists must often endure the harsh 

 marine environment for extended periods of time, 

 forsaking the more comfortable conditions of their 

 offices and homes. I thank all of the participants, 

 scientists, and crews of the NMFS west coast trien- 

 nial surveys. Gary Walters was responsible for bring- 

 ing the cluster analysis program to the AFSC and 

 provided guidance for its use. Mark Wilkins realized 

 this study's benefits and enabled my escape from 

 many routine exercises to complete this work. I am 

 also most grateful to my reviewers, particularly those 

 who witnessed the evolution of this paper. 



Literature cited 



Bray, J. R., and J. T. Curtis. 



1957. An ordination of the upland forest communities 

 of southern Wisconsin. Ecol. Monogr. 27:325-349. 

 Clifford, H. T., and W. Stephenson. 



1975. An introduction to numerical classification. 

 Academic Press, Inc., NY, 229 p. 

 Coleman, B. A. 



1986. The 1980 Pacific west coast bottom trawl sur- 

 vey of groundfish resources: estimates of distribu- 

 tion, abundance, length and age composition. 

 NOAA Tech. Memo. NMFS-F/NWC-100, Alaska 



Fish. Sci. Cent., Natl. Mar. Fish. Serv., NOAA, Se- 

 attle, WA 98115-0070, 181 p. 



Coleman, B. A. 



1988. The 1986 Pacific west coast bottom trawl sur- 

 vey of groundfish resources: estimates of distribu- 

 tion, abundance, length and age composition. 

 NOAA Tech. Memo. NMFS-F/NWC-152, Alaska 

 Fish. Sci. Cent., Natl. Mar. Fish. Serv., NOAA, Se- 

 attle, WA 98115-0070, 145 p. 



Eschmeyer, W. N., and E. S. Herald. 



1983. A field guide to Pacific coast fishes of North 

 America. Houghton Mifflin, Boston, 336 p. 



Fager, E. W., and J. A. McGowan. 



1963. Zooplankton species groups in the North 

 Pacific. Science 140:453-460. 



Gabriel, W. L. 



1982. Structure and dynamics of northeastern Pa- 

 cific demersal fish assemblages. Ph.D. diss., Or- 

 egon State Univ., Corvallis, 298 p. 



Gunderson, D. R., and T. M. Sample. 



1980. Distribution and abundance of rockfish off 

 Washington, Oregon, and California during 1977. 

 Mar. Fish. Rev. 42(3-41:2-16. 

 Lance, G. N., and W. T. Williams. 



1967. A general theory of classificatory sorting strat- 

 egies. I: Hierarchical systems. Comput. J. 1:15-20. 

 Nagtegaal, D. A. 



1983. Identification and description of assemblages 

 of some commercially important rockfishes 

 (Sebaxtes spp.) off British Columbia. Can. Tech. 

 Rep. Fish. Aquat. Sci. Vol. 1, 82 p. 



Richards, L. J., R. Kieser, T. J. Mulligan, 

 and J. R. Candy. 



1991. Classification of fish assemblages based on 

 echo integration surveys. Can. J. Fish. Aquat. Sci. 

 48:1264-1272. 



Rogers, J. B., and E. K. Pikitch. 



1992. Numerical definition of groundfish assem- 

 blages caught off the coasts of Oregon and Wash- 

 ington using commercial fishing strategies. Can. 

 J. Fish. Aquat. Sci. 49:2648-2656. 



Weinberg, K. L., M. E. Wilkins, and T. A. Dark. 



1984. The 1983 Pacific west coast bottom trawl sur- 

 vey of groundfish resources: estimates of distribu- 

 tion, abundance, age and length composition. 

 NOAA Tech Memo. NMFS-F/NWC-70, Alaska Fish. 

 Sci. Cent., Natl. Mar. Fish. Serv., NOAA, Seattle, 

 WA 98115-0070, 376 p. 



Weinberg, K. L., M. E. Wilkins, R. R. Lauth, and 

 P. A. Raymore Jr. 



1994. The 1989 Pacific west coast bottom trawl sur- 

 vey of groundfish resources: estimates of distribu- 

 tion, abundance, and length and age composition. 

 NOAA Tech Memo. NMFS-AFSC-33, Alaska Fish. 

 Sci. Cent., Natl. Mar. Fish. Serv., NOAA, Seattle, 

 WA 98115-0070, 168 p. 



