338 
Fishery Bulletin 116(3-4) 
Table 1 
Data sources for trawl surveys used to examine the spatial distribution of squatinid sharks in the western North Atlantic 
Ocean. Data were collected by the Marine Resources Monitoring, Assessment, and Prediction Program (MARMAP), the 
Northeast Area Monitoring and Assessment Program (NEAMAP), the Northeast Fisheries Science Center (NEFSC), South¬ 
east Area Monitoring and Assessment Program South Atlantic (SEAMAP-SA) and Gulf of Mexico (SEAMAP-GOM) surveys, 
the Southeast Fisheries Science Center (SEFSC) Small Pelagics/Acoustic Trawl Survey, and SEFSC Mississippi Laboratories 
historical and exploratory trawl surveys (MSLABS). n=the total number of trawls conducted over each time series. 
Data source 
Years 
Months sampled 
n 
Spatial coverage 
Depth (m) 
MARMAP 
1973-1980 
Jan-Nov 
1196 
Cape Hatteras, NC, to Cape Canaveral, FL 
3-108 
NEAMAP 
2007-2016 
Apr-May, Sep-Nov 
2870 
Cape Cod, MA, to Cape Hatteras, NC 
4-57 
NEFSC 
1963-2016 
Jan-Dec 
43,121 
Halifax, Nova Scotia, to Cape Canaveral, FL 
2-1164 
SEAMAP-SA 
1989-2015 
Apr-Nov 
16,046 
Cape Hatteras, NC, to Cape Canaveral, FL 
2-20 
MSLABS 
1950-1997 
Jan-Dec 
29,392 
Rhode Island to Brownsville, TX 
4-3085 
SEAMAP-GOM 
1987-2016 
Jun-Jul, Oct-Nov 
16,794 
Key West, FL, to Brownsville, TX 
2-113 
SEFSC 
2002-2016 
Oct-Nov 
1538 
Key West, FL, to Brownsville, TX 
12-555 
limited spatial distribution of some species (Compagno 
et al., 2005). For example, Walsh and Ebert (2007) con¬ 
firmed the validity of 4 species of squatinids around 
Taiwan in the western North Pacific Ocean: Taiwan 
angel shark ( Squatina formosa); Japanese angel shark 
( S. japonica), clouded angel shark (S. nebulosa ); and 
ocellated angel shark (S. tergocellatoides). Similarly, 
Vaz and de Carvalho (2013) described the overlapping 
range of three sympatric squatinids within the western 
South Atlantic Ocean off the coast of Brazil: Argentine 
angel shark (S. argentinaY, angular angel shark ( S. 
guggenheim ); and hidden angel shark (S. occulta). 
Angel sharks inhabiting the WNA off the US east 
coast of the US (EC) and throughout the Gulf of Mexico 
(GOM) are largely thought to consist of a single spe¬ 
cies, the Atlantic angel shark (S. dumeril ) (e.g., Bigelow 
and Schroeder, 1948; Castro, 1983; Compagno, 1984). 
However, Applegate et al. (1979) reported the possible 
presence of an undescribed squatinid in the GOM on 
the basis of a specimen collected in a fish market in 
Mexico. Later, Castro-Aguirre et al. (2006) described 2 
new species of angel sharks, Gulf angel shark (S. het- 
eroptera) and Mexican angel shark (S. mexicana), from 
the GOM. Shortly thereafter, Ebert et al. (2013) placed 
the 2 newly described species in synonymy with S. du¬ 
meril leaving the validity of these species in question, 
a conclusion supported by Eschmeyer and Fricke 1 but 
in disagreement with Castro (2011). Despite the taxo¬ 
nomic uncertainty associated with angel sharks in the 
GOM, the range of Atlantic angel sharks in continental 
shelf and slope waters of the WNA has been reported 
as continuous by some and disjunct by others. For ex¬ 
ample, Compagno (2002) indicated angel sharks within 
the WNA have a continuous range from Massachusetts 
to Veracruz, Mexico, whereas Bigelow and Schroeder 
1 Eschmeyer, W. N., and R. Fricke (eds.). 2017. Cata¬ 
log of fishes. Electronic version, updated 1 November 
2017. [Available from website,] 
(1948) reported that the range extends from southern 
New England to North Carolina off the east coast and 
from the Florida Keys into the northern GOM. 
On the basis of conflicting information regarding 
the range of the genus in US waters of the WNA, our 
goal was to examine fishery-independent data collected 
throughout the region to determine the distribution of 
angel sharks. Our goal was 1) to determine whether 
the range is continuous (or discontinuous) throughout 
US waters of the WNA and 2) to identify spatial dis¬ 
continuities in distribution that could be consistent 
with the idea of multiple species or populations in the 
region. 
Materials and methods 
To examine the broad- scale distribution of squatinids 
in US waters of the WNA, catch data from 7 fishery-in- 
dependent trawl surveys were obtained and analyzed. 
Data were collected from Nova Scotia to the Florida 
Keys off the EC and in the northern GOM from the 
Florida Keys to Brownsville, Texas. The boundary be¬ 
tween the EC and the GOM was designated to be at 
81.0°W. All data sources were trawl based; however, 
because of a lack of consistency in survey design and 
gear configurations among and, in some cases, within 
data sources, we did not compare relative abundance 
(i.e., catch-per-unit-of-effort) throughout the sampling 
area. Additionally, because of numerous changes in 
the experimental design and gear of most surveys, re¬ 
search design and gear specifications are not provided 
in the present study. Data sources from the east coast 
of the US included the 1) National Marine Fisheries 
Service (NMFS), Northeast Fisheries Science Center 
(NEFSC), Spring, Autumn and Winter Bottom Trawl 
surveys (1963-2016); 2) the Northeast Area Monitor¬ 
ing and Assessment Program (NEAMAP) (2007-2016) 
Survey; 3) the joint South Carolina Department of Nat- 
