Ross et al.: Fish species associated with shipwreck and natural hard-bottom habitats 
55 
fauna with a deep (depths of 237-253 m) shipwreck off 
Cape Fear, North Carolina, that was assessed during 
one earlier ROV dive (Quattrini and Ross, 2006). Many 
(-30%) of the reef-associated fishes reported here are 
common on outer shelf hard grounds throughout the 
southeastern United States (Grimes et al., 1982; Quat- 
trini and Ross, 2006), also indicating a warm-temper- 
ate affinity for reef fishes of the southern MAB. 
As with the reefs of the middle to outer shelf, hard- 
bottom habitats of the shallower inner shelf of the 
MAB were dominated by relatively few, but different, 
fish species (i.e., the black sea bass, tautog, cunner, 
and scup). On the deeper hard-bottom habitats sur- 
veyed in this study, the black sea bass, tautog, and 
scup ranked below the top 6 species in abundance. 
Previous shelf studies were conducted in much shal- 
lower water (depths <35 m) (Briggs, 1975; Feigenbaum 
et al., 1985; Eklund and Targett, 1991; Adams, 1993), 
and not many small species were caught in 2 studies 
that relied heavily on data from fish traps. However, 
taxa like the Anthiinae, most common on deeper reefs 
(Anderson and Heemstra, 2012), are unlikely to occur 
on inshore reefs. Although regionally limited in gen- 
eral, hard-bottom habitats and associated data that 
can be recorded there are even more rare along the 
outer shelf (i.e., ~100-m depth zone; Steimle and Zetlin, 
2000). Despite the restricted scope of these deep shelf 
reefs, they support economically important fishes (e.g., 
groupers, tilefishes, and black sea bass) and exhibit a 
high species richness of fishes, as do reefs at similar 
depths south of Cape Hatteras (Parker and Ross, 1986; 
Quattrini and Ross, 2006). 
A degree of faunal stability along the outer shelf of 
the southern MAB is indicated by similarities between 
years or seasons for the 4 study sites sampled in both 
seasons and both years. Although many fish species 
shift distributions by season in the MAB (Murawski 
et al., 1983), such movements may be less pronounced 
in deeper waters. A relatively small (~2°C) variation in 
bottom temperatures along the outer shelf (depth -100 
m) was correlated with consistent groupings of soft- 
bottom species across seasons and years (Colvocoresses 
and Musick, 1984). Grimes et al. (1986) noted that the 
region from southern New England to the MAB was of- 
ten occupied by a warmer (9-14°C) bottom water mass 
from depths of about 100-300 m. In contrast, there 
were distinct seasonal differences in fish communities 
correlated with temperature, which varied over a range 
of 16.7°C, on an artificial reef in much shallower wa- 
ter, at a depth of 21 m, off Virginia (Adams, 1993). For 
the deeper shipwreck sites that we sampled during 2 
seasons, only a mean bottom temperature difference 
<1.5°C was observed between the 2 survey periods. Al- 
though more continuous and long-term environmental 
data are needed to capture more accurate means and 
especially variability, our results agree with the larger 
data set from Colvocoresses and Musick (1984). 
Colton (1972) noted a series of warming and cool- 
ing trends on the shelf in the Gulf of Maine, but there 
was also little apparent change in the distributions of 
4 groundfish species correlated with these tempera- 
ture shifts. Because obligate reef fishes usually exhibit 
strong site or area fidelity, as long as bottom tempera- 
tures remain within tolerances, much of the reef fish 
community (e.g., Anthiinae and Hyporthodus spp.) on 
the outer shelf of the MAB should continue to occupy 
these hard-bottom sites. However, episodic intrusions 
of cold water from the north or from the deep sea can 
jeopardize some species of the reef fish community of 
the MAB outer shelf and could cause mass mortalities 
as documented for tilefish (Marsh et al., 1999). 
As previously suggested (Murawski et al., 1983; Nye 
et al., 2009; Mpller et al., 2010), it is tempting to pro- 
pose that hard-bottom habitats of the southern MAB 
are increasingly invaded by more warm-temperate spe- 
cies, possibly in response to rising ocean temperatures. 
North Carolina is the closest southern source where 
many of the species noted here are abundant on ex- 
tensive outer shelf hard-bottom habitats (Grimes et 
al., 1982; Parker and Mays, 1998; Quattrini and Ross, 
2006). Although Cape Henry, Virginia, was listed with 
question as the northern limit of blueline tilefish (Dool- 
ey, 1978), our observations confirm its presence in the 
MAB (Fig. 2E) and extend its range north of Norfolk 
Canyon. That species, and the yellowfin bass, had been 
reported from this region from the early 20 th century 
(Firth, 1933, 1937). Snowy grouper ( Hyporthodus nive- 
atus) and warsaw grouper ( H . nigritus) (Fig. 2, C and 
D) were reported in New England waters as early as 
the late 19 th century, but in most of these cases the 
fish were juveniles collected inshore and assumed to 
be strays (Smith, 1971). Large adults (documented in 
world tackle records) of snowy grouper recently oc- 
curred in the MAB recreational hook-and-line fishery 
(as did blueline tilefish), but data presented here are 
the first descriptions of their relative abundance and 
adult habitat along the outer shelf of the MAB. Re- 
cent collections of red barbier near Wilmington Canyon 
represent the first records of that species for the MAB 
(Moore et al., 2003), but this small, deep-reef-specific 
fish could have easily escaped detection. Similarly, our 
observations of 3 individuals of roughtongue bass (Pro- 
notogrammus martinicensis) at depths of 92 m on the 
natural hard bottom represent a new northern range 
limit (from North Carolina, Anderson and Heemstra, 
2012) for this species, but this observation does not 
necessarily mean that this species is newly arrived 
to the MAB. Although historical data have been inad- 
equate (because of a lack of appropriate sampling on 
deep reefs) to allow an evaluation of long-term changes 
in the patterns of hard-bottom species composition on 
the MAB outer shelf, this study, the first to examine 
outer shelf reef fishes of this region, should provide a 
baseline for future assessments. 
Acknowledgments 
Funding for this project was supplied by the Bureau of 
Ocean Energy Management (BOEM) (contracted to CSA 
