Grizzle et al.: Effects of a large fishing closure on benthic communities in the western Gulf of Maine 
315 
findings to the naturally dynamic nature of the seafloor 
that is frequently affected by storms and strong tidal 
currents (also see Auster and Langton, 1999; DeAlteris 
et ah, 1999; Henry et al., 2006). Stokesbury and Har- 
ris (2006) reported similar findings for a video study of 
epifauna in the same general study areas. In contrast, 
Collie et al. (2005) showed substantial recovery of ben- 
thic epifauna (megafauna) on gravel bottoms inside 
one of the closed areas on Georges Bank, but differ- 
ences did not occur until 2.5 years after closure, and 
increases in biomass and abundance of some taxa were 
still occurring after five years. They suggested that re- 
covery times for faunal communities on gravel bottoms 
in their study area were on the order of ten years. In 
sum, these data further indicate that long-term studies 
will be needed to fully assess the effects of the WGOM 
closure on the recovery process for benthic communities 
on hard bottoms. 
A similar conclusion can be drawn for recovery of ben- 
thic communities on muddy bottoms inside the closure: 
the recovery process is still ongoing. Previous studies 
that indicate otherwise, however, need to be considered. 
For example, two studies in the western Gulf of Maine 
indicated rapid recovery of mud bottom communities. 
Sparks-McConkey and Watling (2001) reported recovery 
to ambient levels for the infauna on muddy bottoms 
within 3.5 months after experimental trawling distur- 
bance. Simpson and Watling (2006) also found only 
short-term (less than three months) effects on mud-bot- 
tom infaunal communities regularly fished by shrimp 
trawls with rock hopper gear compared to an adjacent 
unfished area. In both studies, the dominant taxa were 
small, nearsurface-dwelling species (mostly polychaetes) 
with high reproductive rates and thus potentially able 
to recover quickly from disturbance. It should also be 
noted that both these studies involved much smaller 
spatial scales (two study areas, each <40 km 2 ) than 
that of our study (515 km 2 ) such that immigration over 
smaller distances may have resulted in faster recovery 
rates. In contrast to these findings of minimal effects 
and fast recovery, some studies have shown substantial 
effects of otter trawls on mud-bottom communities and 
long recovery times, and the differences can in part 
be explained by differences in dominant taxa. If mud 
bottom communities include long-lived species, many 
of which are also structure-forming, then trawls (and 
other mobile gear) can have substantial adverse ef- 
fects, as was found in the meta-analysis of Collie et 
al. (2000). Jennings et al. (2001) and Queiros et al. 
(2006) found significant decreases in infaunal biomass 
and production on muddy bottoms related to trawling 
intensity, as well as differential responses in relation 
to size spectra of the dominant taxa. Hixon and Tissot 
(2007) documented 600% higher densities of epibenthic 
invertebrates (and 23% more fish) based on video tran- 
sects in untrawled (compared to trawled) mud bottom 
areas. Long-lived, slow-growing sea pens (Stylatula 
spp.) dominated the invertebrate communities in un- 
trawled areas, but were rare in trawled areas. Tillin 
et al. (2006) reported similar sea-basin scale patterns 
in benthic communities in the North Sea in relation 
to fishing intensity; large, suspension-feeding epiben- 
thic taxa dominated in lightly trawled areas, whereas 
mobile taxa and infaunal and scavenging species were 
dominant in areas that were more heavily trawled. 
Therefore, the level of effect and recovery times for 
benthic communities on mud bottoms affected by bot- 
tom trawls can be expected to vary widely, dependent 
in part on characteristics of the dominant species, and 
areas dominated by large or structure-forming taxa can 
be the most negatively affected. Further studies will 
be required to characterize the process over the long 
term, and such research should include more rigorous 
assessment of variations in fishing intensity than was 
possible in our study (Hiddink et al., 2006). 
A final topic here concerns possible indirect effects 
on benthic communities caused by removal of fishing 
pressure on species that consume benthic invertebrates 
(Pinnegar et al., 2000). Unfortunately, little information 
is available on how fish populations have responded to 
the WGOM closure. However, available data indicate lit- 
tle or no increase in populations of fish such as gadids, 
skates, and flatfish that prey on benthic invertebrates 
(Murawski et al., 2004, 2005). However, recent exper- 
imental tethering studies showed greater predation 
rates on adult crabs ( Cancer spp.) in rocky areas inside 
the closure (Meyer, 2005). Meyer also found very slow 
colonization rates on experimental habitat plots inside 
and outside of the closure, and no significant effects of 
predator exclusion cages on these rates. In sum, these 
data suggest that any indirect effects caused by dif- 
ferential predation rates inside compared to outside of 
the closure would have been weak. Meyer’s (2005) colo- 
nization experiments (which were conducted over 4- to 
12-month periods) also indicate that any recovery rates 
occurring inside the closure would be relatively slow. 
The WGOM closure area is achieving a very impor- 
tant management goal: protection and enhancement 
of seafloor habitats. How are these changes related to 
ongoing recoveries of some fish populations and what 
are the management implications? 
Closed area management measures are expected to 
have two separate effects on productivity and sustain- 
ability of fisheries (Stefansson and Rosenberg, 2005). 
First, if the closure is properly designed, it may reduce 
fishing mortality rates on some stocks by shifting lim- 
ited effort away from areas where catchability is high 
to areas where it is lower. Effort control is essential to 
ensure that effort increases don’t compensate for re- 
duced catchability. Reduced fishing mortality rates on 
overfished stocks should increase productivity through 
higher stock and recruitment levels. 
Secondly, closed areas that protect habitat may in- 
crease productivity of stocks by increasing growth, re- 
production, and survival rates. This effect of closed 
areas is much harder to quantify or demonstrate with 
respect to recovery of the fish stocks. But, one impor- 
tant aspect of inferred habitat quality is the abundance 
of food resources for fishes, including both infauna and 
epifauna. 
