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Fishery Bulletin 106(4) 
Table 2 
(A) Effects of disturbance from mobile fishing gear and year on the composition of noncolonial organisms at shallow sites. 
In this two-way crossed analysis of similarity (ANOSIM) test, the sample global R is the test statistic. Data were per- 
muted 9999 times to generate an empirical frequency distribution for global R. Significance levels: *P<0.05; ***P<0.001. 
(B) Similarity of percentages (SIMPER) results identifying species that are characteristic of disturbed and undisturbed sites at 
the shallow depth stratum. Cumulative percentage refers to the contribution that species make to either the cumulative similar- 
ity within each group or the cumulative dissimilarity between two groups. Results are presented in terms of similarity among 
disturbed transects, similarity among undisturbed transects, and dissimilarity between disturbance groups. 
A ANOSIM results 
95th percentile 
Factor 
of permuted global R’s 
Sample global R 
Disturbance 
0.14 
0.20* 
Year 
0.12 
0.30*** 
B SIMPER results 
Similarity among disturbed transects (i.e., outside CA-II) 
Mean density 
Cumulative 
Scientific name 
per photograph 
percentage 
Pagurus spp. 
0.40 
27.55 
Asterias spp. 
0.32 
48.41 
Placopecten magellanicus 
0.59 
63.17 
Siphons of unidentified bivalves 
0.51 
74.24 
Cyclocardia borealis 
0.24 
82.70 
Similarity amongst undisturbed transects ( 
i.e., inside CA-II) 
Mean density 
Cumulative 
Scientific name 
per photograph 
percentage 
Placopecten magellanicus 
0.72 
43.58 
Pagurus spp. 
0.42 
67.24 
Strongylocentrotus droebachiensis 
0.30 
78.10 
Asterias spp. 
0.27 
88.39 
Dissimilarity between disturbance groups 
Mean density 
Mean density 
Cumulative 
Scientific name 
at disturbed sites 
at undisturbed sites 
percentage 
Placopecten magellanicus 
0.59 
0.72 
12.68 
Siphons of unidentified bivalves 
0.51 
0.09 
21.74 
Pagurus spp. 
0.40 
0.42 
30.46 
Asterias spp. 
0.32 
0.27 
39.07 
Strongylocentrotus droebachiensis 
0.04 
0.30 
46.32 
Astarte spp. 
0.47 
0.06 
52.49 
transects inside CA-II (i.e., P. magellanicus, Pagurus 
spp., S. droebachiensis, and Asterias spp., Table 2B), all 
increased in abundance from 1994 through 2000 (Figs. 
3A and 6). Of particular note was the nearly tenfold 
increase in the mean density of P. magellanicus during 
this time period. At deep sites, seven of the ten taxo- 
nomic groups that contributed the most to dissimilar- 
ity among disturbance categories were more abundant 
along undisturbed transects (Table 3B). As was the 
case at shallow sites, hard-shelled mollusks ( Astarte 
spp. and the waved whelk [. Buccinum undatum ]) and 
scavengers, such as Pagurus spp., characterized deep, 
disturbed sites. 
At both depths, species richness of noncolonial epi- 
fauna peaked along undisturbed transects (Fig. 7). The 
negative relationship between species richness and hot- 
