BODKIN: MACROCYSTIS AND NEREOCYSTIS KELP FORESTS 



Midwater Transects 



Differences in abundance of fish in the Macro- 

 cystis and Nereocystis forests were most apparent 

 among the midwater species, primarily within the 

 genus Sebastes. Of the nine species of midwater fish 

 (juvenile Sebastes treated as a single "species"), 

 three were significantly more abundant in Macro- 

 cystis than in Nereocystis forests: blue rockfish, S. 

 mystinus; kelp rockfish, S. atrovirens; and olive 

 rockfish, 5. serranoides (Tables 1, 2). A fourth 

 species, the black rockfish, S. melanops, was not ob- 

 served on Nereocystis transects, though it was only 

 occasionally seen in Macrocystis. 



Although there were no general changes in fish 

 abundance between 1982 and 1983 among the mid- 

 water species, some individual species differences 

 were noted. Densities of blue rockfish were signifi- 

 cantly lower in 1983 than in 1982 (Table 2). During 

 this same period there was an insignificant increase 

 in the density of juvenile rockfish. Densities of the 

 senorita, Oxyjulis californica, appeared to increase 

 within both forest types in 1983, but the increase 

 was significant only when canopy types were com- 



bined for each year. This annual variation should be 

 considered in light of the extremely anomolous El 

 Nino event which occurred during this period (Cane 

 1983), and may be atypical. 



Benthic Transects 



Among the 19 principally benthic species found 

 in both the Macrocystis and Nereocystis benthic 

 transects, three (16%) were significantly more abun- 

 dant in Macrocystis forests: Striped seaperch, 

 Embiotoca lateralis, painted greenling, Oxylebius 

 pictus, and the gopher rockfish, Sebastes carnatus 

 (Tables 1, 3). One other species, the kelp rockfish, 

 which occurred on benthic transects, was considered 

 as primarily a midwater species. Gopher rockfish are 

 bathymetrically segregated from the sibling species, 

 S. chrysomelas (black-and-yellow rockfish). Gopher 

 rockfish are relatively more abundant at depths >12 

 to 14 m (Larson 1980). In my study, the densities 

 of black-and-yellow rockfish increased significant- 

 ly in the second year while during the same period, 

 densities of gopher rockfish decreased. 



Due to sampling methodology and the occurrence 



Table 2.— Mean densities (no. fish/100 m 2 ) and frequency of occurrence of fishes on midwater transects through 



kelp (standard error of mean in parenthesis). 



1 Difference significant between Macrocystis and Nereocystis, years combined. 



2 Difference significant between years, kelp canopies combined. 



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