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Fishery Bulletin 106(1 ) 
stations shared a number of dominant species, whereas 
the assemblage of inshore stations varied along both 
axes. The species composition at each inshore station 
was not only different from the near-ridge+offshore 
stations but also from each other (Table 2, Fig. 5D). 
Within the inshore group, BHR-3 was characterized 
by American sand lance (Ammodytes americanus ) and 
gobies (Gobiosoma spp.), and BHR-5 was differentiated 
as the only station with weakfish ( Cynoscion regalis). 
The remaining inshore stations were differentiated 
from other stations, and to some degree each other, 
by the abundance of Atlantic croaker ( Micropogonias 
undulatus ) and kingfish (Menticirrhus spp.). Less than 
half (39%) of the species identified were captured in 
both assemblages (Table 2), and no species were shared 
among the top five species loading scores for each 
assemblage. 
BHR1 BMR 2 BMR 3 BHR 4 BHR 5 BHR 6 BHRTOP BMR 7 BHR 9 BHR ID BUR 15 
Sampling locations 
Figure 3 
Mean abundance per tow (CPUE) and mean number of 
species per tow (RPUE) by sampling location for the otter 
trawl surveys (A and C) in 2001-06 and beam-trawl surveys 
( B and D ) in 1991-95. Vertical lines represent standard error. 
Sampling locations with different superscripts are significantly 
different from each other at the alpha=0.05 level. See Figure 
1 for station locations. 
Over 60% of the variance in the species-environment 
interaction was reflected in both the mid- and late sum- 
mer ordinations (Table 5). Temperature and habitat 
complexity were the dominant environmental variables 
shaping the late summer ordination (Table 6). The ar- 
rangement of the species assemblages in relation to the 
station assemblages was similar to that produced with 
correspondence analysis (CA), providing confidence that 
constrained ordination gave a satisfactory picture of 
realized distribution. 
Fish-assembiage structure based on otter-trawl samples 
Three assemblages were apparent in the otter-trawl 
data regardless of season: inshore (BHR-1), near-ridge 
(BHR-5, BHR-6, BHRTOP, and BHR-7), and offshore 
(BHR-9, BHR-10, and BHR-11) (Fig. 6). Seasonally, the 
near-ridge and offshore assemblages overlapped 
little in midsummer (Fig. 6A) and were discrete in 
late summer (Fig. 6B). In midsummer, the near- 
ridge assemblage was spread along both axes, 
indicating differences between samples, and the 
offshore assemblage was more compact, indicat- 
ing a greater similarity in samples (Fig. 6A). In 
late summer the assemblage configurations were 
reversed (Fig. 6B). All three assemblages shared a 
majority of species, although there were some dif- 
ferences in the abundance of each species (Tables 
3 and 4; Fig. 6, C and D). 
The seasonal difference in assemblages result- 
ed from a change in both the number and iden- 
tity of species present in the study area (Tables 
3 and 4; Fig. 6, C and D). In midsummer the 
inshore assemblage was composed predominately 
of northern pipefish (Syngnathus fuscus) and 
other species were present in lesser numbers (Ta- 
ble 3; Fig. 6C). The near-ridge assemblage was 
dominated by butterfish ( Peprilus triacanthus) 
and bay anchovy ( Anchoa mitchilli ), and only 
striped anchovy (Anchoa hepsetus) and spotted 
hake ( Urophycis regia) were present with a mean 
catch per tow greater than one (Table 3). Al- 
though butterfish was also the dominant species 
in the offshore assemblage, its abundance was 
one third of what was found in near-ridge trawls 
(Table 3). Of particular interest in the midsum- 
mer analysis was a group of species (weakfish, 
bluefish [ Pomatomus saltatrix], northern puff- 
er [Sphoeroides maculatus], bay anchovy, and 
striped anchovy) separated along the primary 
axis from the rest of the species centroids in the 
near-ridge assemblage. These species were as- 
sociated with samples from near-ridge stations 
taken in 2001 and 2005 (Fig. 6A). During late 
summer, the abundance of bay anchovy increased 
substantially within the inshore assemblage, as 
did the abundance of northern pipefish (Table 4, 
Fig. 6C). At that time, bay anchovy was the most 
abundant species in the near-ridge assemblage 
by nearly two orders of magnitude, and Atlantic 
