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Fishery Bulletin 100(4) 



that result in offshore transport (Magnell et al.. 1990). 

 Likewise, Monterey Canyon may act as a distributional 

 barrier because continental shelf habitats constrict se- 

 verely, creating a potential bottleneck to dispersion. Some 

 support for this hypothesis is evident in the rockfish dis- 

 tributional maps (Figs. 6-10), which show that shallow 

 water species are more likely to have Monterey Canyon as 

 a distributional boundary when compared to the deeper 

 dwelling species, for which there apparently exists ample 

 habitat. 



Overall, depth appears to be the single most important 

 determinant of rockfish distributions. Most of the abun- 

 dance patterns we observed followed the distribution of 

 habitats by depth. Species diversity in the study area also 

 seemed to follow the pattern of depth habitat distribution. 

 However, species richness did not follow this pattern, but 

 instead followed the region of overlap between shelf and 

 slope rockfish assemblages. In fact, the contoured ridge 

 of highest richness may be useful in spatially delineating 

 the shelf and slope assemblages. This ridge appeared to 



