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Fishery Bulletin 107(3) 
(on sand sediments) was likely underestimated by our 
data, and the negative impact of gillnets (on gravel) was 
likely over estimated. 
Discussion 
In control-impact studies like this one, spatial effects 
cannot typically unambiguously be distinguished from 
temporal effects of the activity of interest, because no 
data are available from before the activity was started 
(Osenberg et al., 1994). Hence, such studies (in con- 
trast to the more rigorous before-after, control-impact 
[BACI] designs) must be assessed with respect to how 
factors that may have changed over time in relation to 
the control and impact areas might have contributed 
to any observed differences. Thus, it is possible that 
there were differences in the benthic communities before 
the WGOM closure was implemented that could have 
affected our interpretation of the data. Although this 
possibility cannot be unequivocally discarded, several 
lines of evidence indicate it is reasonable to assume simi- 
lar conditions in both areas before the closure. First, the 
overall study area was chosen so that the control sites 
with continued fishing outside the closure were in close 
proximity to the treatment sites inside the closure where 
fishing impacts were removed; this proximity of the 
two areas minimized potential confounding differences 
related to distance. Second, the range of habitat types 
and relative coverage area by each type were similar 
inside and outside the closure. Finally, we know of no 
other events since establishment of the closure — other 
than fishing gear restrictions and subsequent intensity 
patterns — that may have differentially affected the 
study areas inside and those outside the closure. There- 
fore, although we feel it is reasonable to interpret the 
differences inside and outside the closure in our data 
mainly to be the result of the removal of gillnets and 
otter trawls from the closed area, details on the spatial 
distribution patterns for each type of gear use must be 
considered in order to fully assess these impacts. 
The obvious intent behind the WGOM closure was to 
eliminate negative impacts from both gear types inside 
the closure. Implementation of the closure, however, 
also caused a shift in fishing intensity, particularly for 
gillnets. Although this shift did not affect the overall 
conclusion of significant impacts for both gear types 
and subsequent recovery inside the WGOM closure, it 
does indicate that the relative levels of impact of the 
two gear types may have been exaggerated by our data: 
the impacts of gillnets may have been over-estimated 
because of the substantially increased postclosure fish- 
ing intensity outside, and the trawl impacts may have 
been under-estimated. Displacement of fishing effort 
and intensity may be the general trend for fishing clo- 
sures, and there is no straightforward way to estimate 
the magnitude of this effect (Ward, 2004; Fogarty and 
Murawski, 2005). 
The major conservation concerns regarding the use 
of gillnets have been bycatch and entanglement of non- 
target species (He, 2006). Our data, however, strongly 
indicate that gillnets have been responsible for substan- 
tial reductions in epifauna on Jeffreys Ledge. Although 
Malik and Mayer (2007) reported seafloor marks on 
top of the ledge which may be evidence of the use of 
other bottom fishing gear in this area, available fishing 
activity data on preclosure and postclosure gear use 
in the study area indicate that gillnets are the major 
gear used on rocky bottoms in the area. Therefore, the 
substantial and significant differences between epifauna 
densities and taxonomic richness inside (compared to 
outside) the closure would indicate that macrofaunal 
communities on hard bottoms were damaged by gillnets 
and are recovering from these effects. 
Our data from soft-sediment areas where otter trawls 
were the dominant gear type reflect the general trends 
observed in other studies (see reviews by Dorsey and 
Pederson, 1998; Watling and Norse, 1998; Johnson, 
2002; and Kaiser et al., 2006): decreased density, bio- 
mass, and taxonomic richness in benthic communities. 
To our knowledge, only one previous study of bottom 
habitats inside the WGOM closure has been completed, 
an M.S thesis by Knight (2005). This research focused 
on areas north of our study area that were mainly af- 
fected by trawls, and it also had a similar study design 
of inside vs. outside a closure. The sampling occurred 
from 2002 through 2004, covering nearly the same time 
interval as our project, but also included areas in the 
easternmost portion of the WGOM closure that were 
not incorporated into the closure area until 1999 (two 
years after the initial closure area was implemented). 
These differences aside, Knight (2005) reported find- 
ings similar to ours: much higher abundances for some 
infaunal and epifaunal taxa inside the closure compared 
to outside. Knight (2005) also noted that a shift in taxo- 
nomic composition of infauna (e.g., increases in sabellid 
polychaetes inside the closure) and epifauna towards 
taxa less tolerant of physical disturbances had occurred 
at sites inside the closure. 
As already noted, our data indicate substantial recov- 
ery but cannot be used to accurately infer the magni- 
tude of recovery because of concurrent and confounding 
changes in fishing intensity during the study period. 
Additionally, our understanding of the recovery process 
for seafloor habitats disturbed by fishing gears is in the 
early stages — in large measure because of the number of 
factors involved (e.g., gear type, frequency and intensity 
of gear disturbances, and seafloor sediment type). Re- 
cent meta-analyses of gear effects have revealed widely 
variable recovery times, and no consistent trends for 
many combinations of gear and bottom types (Collie et 
al., 2000; Kaiser et al., 2006). In two recent studies on 
nearby Georges Bank in the Gulf of Maine few mea- 
surable effects of two large fishing closures were found 
for epifauna and infauna. Link et al. (2005) reported 
no significant differences in a variety of measures of 
benthic communities from video recordings and grab 
samples when comparing sites fished mainly by scallop 
dredges outside the closed areas with those inside the 
closures 4.5 years after closure. They attributed their 
