101 
NOAA 
National Marine 
Fisheries Service 
Fishery Bulletin 
rtr established 1881 
Spencer F. Baird 
First U.S. Commissioner 
of Fisheries and founder 
of Fishery Bulletin 
Spatiotemporal overlap of spiny dogfish 
iSqualus acanthias ) and commercial fisheries in 
the northeast U.S. shelf large marine ecosystem 
Email address for contact author: s.sagarese@rsmas.miami.edu 
1 School of Marine and Atmospheric Sciences 
Stony Brook University 
Stony Brook, New York 1 1794-5000 
Present address for contact author: Cooperative Institute for Marine and Atmospheric Studies 
Rosenstiel School of Marine and Atmospheric Sciences 
University of Miami 
4600 Rickenbacker Causeway 
Miami, Florida 33149 
2 Northeast Fisheries Science Center 
National Marine Fisheries Service, NOAA 
166 Water Street 
Woods Hole, Massachusetts 02543 
Abstract— Commercial fishermen 
have argued that localized concen- 
trations of spiny dogfish ( Squa - 
lus acanthias) in the northeast U.S. 
shelf large marine ecosystem (NES 
LME) have impeded their fishing 
operations when monitoring surveys 
estimated lower relative abundances. 
Fishery-dependent and -independent 
data were analyzed simultaneously 
to examine whether increased spa- 
tial overlap between spiny dogfish 
and commercial fisheries may ex- 
plain high catches of this species on 
fishing grounds. Spatial overlap was 
quantified between spiny dogfish 
distribution and commercial fisher- 
ies from 1989 to 2009 during au- 
tumn and spring in the NES LME. 
Combined, the sink gillnet (SGN) 
and otter trawl (OT) fisheries ac- 
counted for the majority of spiny 
dogfish catch (autumn: 85%; spring: 
92%), either retained (SGN) or dis- 
carded (OT). Centers of spiny dog- 
fish abundance illustrated spatial 
differences in local density within 
the NES LME and revealed seasonal 
differences in spiny dogfish density. 
Recent increases in spatial overlap 
indicate that a growing portion of 
the spiny dogfish stock was available 
to each fishery over the time series. 
Availability, estimated as the per- 
centage of spiny dogfish present on 
fishing grounds, also increased and 
was generally higher during autumn 
than spring. Abundance of mature 
(total length >80 cm) female spiny 
dogfish was significantly related to 
availability, but trends were vari- 
able between fisheries and seasons. 
Although recent increases in abun- 
dance indicate recovery, research 
regarding the mechanisms behind 
these changes may help explain why 
abundance in the NES LME appears 
highly variable. 
Manuscript submitted 21 November 2013. 
Manuscript accepted 21 January 2015. 
Fish. Bull. 113:101-120 (2015). 
doi: 10.7755/FB. 113.2.1 
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. 
Skyler R. Sagarese (contact author ) 1 
Michael G. Frisk 1 
Robert M. Cerrato 1 
Kathy A. Sosebee 2 
John A. Musick 3 
Paul J. Rago 2 
3 Virginia Institute of Marine Science 
College of William & Mary 
P.O. Box 1346 
Gloucester Point, Virginia 23062 
The recent recovery, with increased 
abundance, of spiny dogfish ( Squalus 
acanthias) in the late 2000s in the 
northeast U.S. shelf large marine 
ecosystem (NES LME) is considered 
a success; however, it remains un- 
clear what mechanisms are behind 
recent catches regarded as “unac- 
ceptably high” by fishermen (Tal- 
lack and Mandelman, 2009) and the 
increase in abundance observed in 
monitoring surveys since 2006 (Rago 
and Sosebee 1 ). Large fluctuations in 
1 Rago, P. J., and K. A. Sosebee. 2013. 
Update on the status of spiny dogfish 
in 2013 and projected harvests at the 
Fmsy Proxy and Pstar of 40%. Report 
to the Mid-Atlantic Fishery Manage- 
ment Council Scientific and Statistical 
Committee, 51 p. [Available at http:// 
www.nefsc.noaa.gov/program_review/ 
spiny dogfish abundance derived 
from Northeast Fisheries Science 
Center (NEFSC) bottom trawl sur- 
veys contrast with the expected dy- 
namics of a species with a “slow” life 
history (Musick, 1999), namely late 
age at maturity, low fecundity, and 
slow growth (Nammack et al., 1985). 
Spiny dogfish have experienced 
varying levels of exploitation since 
the reporting of commercial land- 
ings in the 1960s. Although foreign 
fishing fleets harvested substantial 
amounts (mean: 11,310 metric tons 
[t] [standard deviation (SD) 7900]) 
of spiny dogfish before the establish- 
ment of the U.S. Exclusive Economic 
background2014/TOR3TerceiroDogfish 
2013%20Stat°us% 20Report%20and%20 
Projections.pdf.] 
