261 
NOAA 
National Marine 
Fisheries Service 
Fishery Bulletin 
<%• established 1881 
Spencer F. Baird 
First U.S. Commissioner 
of Fisheries and founder 
of Fishery Bulletin 
Assessing the use of a camera system within an 
autonomous underwater wehicle for monitoring the 
distribution and density of sea sollops IPIacopecten 
mageHanicm} in the Mid-Atlantic Bight 
Abstract~The sea scallop (Placo- 
pecten magellanicus) fishery in the 
Atlantic is assessed during annual 
surveys by using both dredging 
and surface-deployed imaging tech- 
niques. In this pilot study in the 
Mid-Atlantic Bight, we used an au- 
tonomous underv/ater vehicle (AUV) 
to photograph the seafloor and to 
evaluate its use for determining 
scallop density and size. During 22 
surveys in 2011, 257 km of seafloor 
were photographed, resulting in over 
203,000 color images. Using trained 
annotators and photogrammetric 
software, we determined scallop 
density and shell heights for 15,252 
scallops. The inshore scallop grounds 
near Long Island (at depths <40 m) 
had a density of 0.077 scallops per 
m^, whereas the inshore grounds 
of the New York Bight had a den- 
sity of 0.012 scallops per m^. Shell 
heights derived from images were 
found to agree well with measure- 
ments from scallops collected with 
a commercial dredge. We show that 
images obtained with an AUV can be 
used to reliably estimate both den- 
sity and shell height consistent with 
direct sampling from the same area. 
Moreover, side-scan sonar images 
obtained v/ith an AUV can be used 
to detect dredge scars and, there- 
fore, can provide a simultaneous, 
relative estimate of fishing effort in 
that area. AUVs provide a highly ac- 
curate suite of data for each survey 
site and therefore allow the design 
of experimental studies of fishing 
practices. 
Manuscript submitted 9 April 2015. 
Manuscript accepted 22 March 2016. 
Fish. Bull. 114:261-273 (2016). 
Online publication date: 26 April 2016. 
doi: 10.7755/FB.114.3.1 
The views and opinions expressed or 
implied in this article are those of the 
author (or authors) and do not necessarily 
reflect the position of the National 
Marine Fisheries Service, NOAA. 
Justin H= Walker’ 
Arthur C. Trembanis (contact author)’'* 
Douglas C, Miller* 
Email address for contact author: art@udel.edu 
’ Department of Geological Sciences 
University of Delaware 
109 Penny Hail 
Newark, Delaware 19716 
2 School of Marine Science and Policy 
University of Delaware 
Lewes, Delaware 19958 
The sea scallop iPlacopecten magel- 
lanicus, Gmelin 1791) of the Mid- 
Atlantic Bight Atlantic fishery has 
been commercially active for over 100 
years, and in recent years has con- 
sistently ranked in the top five most 
valuable domestic U.S. fisheries at 
around a half billion dollars (NMFS, 
2009-2013). To promote the sustain- 
ability of the sea scallop fishery, the 
National Marine Fisheries Service 
(NMFS) monitors the fishery annually 
through a combination of survey ap- 
proaches (Stokesbury et al., 2004; Kel- 
lyi; DuPaul and Rudders^; NEFSC^; 
’ Kelly, K. H. 2007. Results from the 
2006 Maine sea scallop survey, 34 p. 
Maine Dep. Mar. Res., W. Boothbay Har- 
bor, ME. [Available at website.) 
2 DuPaul, W. D., and D. B. Rudders. 
2008. An assessment of sea scallop 
abundance and distribution in selected 
closed areas: Georges Bank area I and 
II, Nantucket Lightship and Elephant 
Trunk. VIMS Mar. Res. Rep. 2008-3, 47 
p. Virginia Institute of Marine Science, 
College of William and Mary, Gloucester 
Point, VA. [Available at website.] 
® NEFSC (Northeast Fisheries Science 
Center). 2010. 50th northeast re- 
gional stock assessment workshop (50th 
Rudders and DuPauF). The results of 
these monitoring efforts are used to 
determine annual catch limits that 
balance overfishing and sustainabil- 
ity against potentially unnecessary 
economic loss (Rosenberg, 2003; Nai- 
du and Robert, 2006). 
The sea scallop fishery stock is 
monitored by means of both dredge 
surveys (DuPaul and Rudders^; 
NEFSC^), and drop-camera surveys 
(Jacobson et al., 2010; Carey and 
Stokesbury 2011; Stokesbury, 2012; 
Hart et al., 2013). Dredging is per- 
formed by towing either a commer- 
cial or scientific survey dredge across 
the seafloor and has a direct impact 
on scallops, bycatch organisms, and 
SAW) assessment report. Northeast 
Fish. Sci. Cent. Ref. Doc. 10-17, 844 p. 
[Available at website.) 
^ Rudders, D. B., and W. D. DuPaul. 
2012. An assessment of sea scallop 
abundance and distribution in open 
access areas: New York Bight and the 
southern New England area. VIMS 
Mar. Res. Rep. 2012-8, 48 p. Virginia 
Institute of Marine Science, College of 
William and Mary, Gloucester Point, 
VA. [Available at website.) 
