308 
Effects of a large fishing closure on benthic 
communities in the western Gulf of Maine: 
recovery from the effects of gillnets 
and otter trawls 
Raymond E. Grizzle (contact author ) 1 
Larry G. Ward 2 
Larry A. Mayer 3 
Mashkoor A. Malik 3 
Andrew B. Cooper 4 
Email address for contact author: ray.grizzle@unh 
1 Department of Biological Sciences 
and Jackson Estuarine Laboratory 
University of New Hampshire 
Durham, New Hampshire 03824 
2 Department of Earth Sciences 
Center for Coastal and Ocean Mapping 
and Jackson Estuarine Laboratory 
University of New Hampshire 
Durham, New Hampshire 03824 
3 Center for Coastal and Ocean Mapping 
University of New Hampshire 
Durham, New Hampshire 03824 
4 Resource and Environmental Management 
Simon Fraser University 
Vancouver, British Columbia V6B 5K3 
Holly A. Abeels 5 
Jennifer K. Greene 6 
Melissa A. Brodeur 7 
Andrew A. Rosenberg 8 
edu 
5 Coastal Watershed Institute 
Florida Gulf Coast University 
Fort Myers, Florida 33965 
6 The Nature Conservancy 
Eastern Resource Office 
1 1 Avenue De Lafayette, 5th Floor 
Boston, Massachusetts 02111 
7 Consortium for Ocean Leadership 
1201 New York Avenue, NW, Suites 400-420 
Washington, D C. 20005 
8 Department of Natural Resources and 
Ocean Process Analysis Laboratory 
University of New Hampshire 
Durham, New Hampshire 03824 
Abstract — The recovery of benthic 
communities inside the western Gulf 
of Maine fishing closure area was 
evaluated by comparing invertebrate 
assemblages at sites inside and out- 
side of the closure four to six years 
after the closure was established. The 
major restriction imposed by the clo- 
sure was a year-round prohibition of 
bottom gillnets and otter trawls. A 
total of 163 seafloor sites (-half inside 
and half outside the closure) within 
a 515-km 2 study area were sampled 
with some combination of Shipek grab, 
Wildco box corer, or underwater video. 
Bottom types ranged from mud (silt 
and clay) to boulders, and the effects 
of the closure on univariate measures 
(total density, biomass, taxonomic 
richness) of benthos varied widely 
among sediment types. For sites 
with predominantly mud sediments, 
there were mixed effects on inside 
and outside infauna and no effect on 
epifauna. For sites with mainly sand 
sediments, there were higher density, 
biomass, and taxonomic richness for 
infauna inside the closure, but no sig- 
nificant effects on epifauna. For sites 
dominated by gravel (which included 
boulders in some areas), there were no 
effects on infauna but strong effects 
on epifaunal density and taxonomic 
richness. For fishing gear, the data 
indicated that infauna recovered in 
sand from the impacts of otter trawls 
operated inside the closure but that 
they did not recover in mud, and 
that epifauna recovered on gravel 
bottoms from the impact of gillnets 
used inside the closure. The magni- 
tudes of impact and recovery, however, 
cannot be inferred directly from our 
data because of a confounding factor 
of different fishing intensities outside 
the closure for a direct comparison of 
preclosure and postclosure data. The 
overall negative impact of trawls is 
likely underestimated by our data, 
whereas the negative impact of gill- 
nets is likely overestimated. 
Manuscript submitted 30 June 2008. 
Manuscript accepted 9 March 2009. 
Fish. Bull. 107:308-317 (2009). 
The views and opinions expressed 
or implied in this article are those 
of the author and do not necessarily 
reflect the position of the National 
Marine Fisheries Service, NOAA. 
The Western Gulf of Maine (WGOM) 
closure area was implemented by the 
National Marine Fisheries Service 
on 1 May 1998 as part of an over- 
all effort to rebuild overfished New 
England groundfish stocks such as 
cod (Gadus morhua), haddock ( Mela - 
nogrammus aeglefinus), other gadids, 
and flatfish. The WGOM closure is 
one of the largest year-round closures 
in the United States, designed to pro- 
tect habitat and help in the recov- 
ery of overfished species. The major 
restriction imposed by the closure 
was year-round prohibition of com- 
mercial fishing gear that is capable 
of capturing groundfish, principally 
otter trawls and gillnets. A variety of 
other fishing gears (e.g., lobster pots, 
recreational hook-and-line gear), how- 
ever, have been deployed in the area 
since its establishment. The WGOM 
closed area fits the definition of a 
marine protected area (MPA) because 
it provides some level of protection of 
habitat and resources (NRC, 2002). 
In many areas, MPAs have been 
useful management tools but the 
causal mechanisms for their effec- 
tiveness in protecting habitat and 
meeting other management objectives 
differ widely, largely because MPAs 
vary widely in design and other char- 
acteristics (Fogarty and Murawski, 
2005; Shipley, 2004). Hence, there 
is a need to assess individual MPAs 
in the context of environmental and 
other characteristics, as well as in 
regard to the particular combination 
of restrictions placed on each area. 
For assessing the data presented 
here, the closure was considered as 
an area that was potentially recover- 
ing from the impacts of gillnets and 
otter trawls. 
There have been no published stud- 
ies on the effects of the WGOM clo- 
sure on seafloor habitats, and none 
designed specifically to address the 
effects of the closure on groundfish 
