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Fishery Bulletin 115(3) 
only predators 
Figure 7 
Average abundance, measured as number of individuals per 
grouper pit, of large fish, including large grunts such as the 
margate ( Haemulon album) and cottonwick ( Haemulon mel- 
anurum), snapper ( Lutjanus spp.), grouper ( Mycteroperca spp, 
Epinephelus spp., and the graysby, Cephalopholis cruentata), 
triggerfish ( Balistes spp.), and the hogfish ( Lachnolaimus max- 
imus), associated with grouper pits surveyed during 2012-2015 
off southwestern Florida, shown for each predator presence or 
absence category: no predator; red grouper ( Epinephelus morio) 
only; species of lionfish ( Pterois spp.) only; or both predators. 
The P-value is given for results from the Kruskal-Wallis test. 
Statistically significant differences are noted with different let- 
ters (a-c). Error bars indicate standard errors of the mean 
was conducted by Albins (2013), native fish communi- 
ties on shallow-water patch reefs in the Bahamas were 
compared when a native grouper (the coney [ Cephalo- 
pholis fulva ]), the lionfish, both predators together, and 
neither predator was present. Lionfish were found to 
cause a reduction in abundance of small, native coral- 
reef fishes 2.5 times greater than the reduction caused 
by the native piscivore. Lionfish also caused a reduc- 
tion in the species richness of small coral-reef fishes, 
whereas the native piscivorous grouper had no signifi- 
cant effect. We observed no negative effects of presence 
of lionfish on the fish communities associated with 
mesophotic red grouper pits. Instead, pits with lionfish 
had both greater species diversity and species richness, 
and they had higher abundances of some fish species. 
Although limited in number, other studies also have 
reported no negative effect from the invasion of lionfish. 
Elise et al. (2015), for example, found no significant 
change in the structure of the native fish assemblage 
or in species richness and density of potential lionfish 
prey, predators, and competitors over time with the ar- 
rival of lionfish in the Archipelago Los Roques National 
Park, Venezuela. In fact, species richness of predators 
and competitors of lionfish and density of predators of 
lionfish were higher where lionfish were present. They 
attributed this result to habitat characteristics and 
good abiotic conditions supporting high species rich- 
ness and density of prey. Lionfish may therefore ac- 
tively select areas where species richness and 
prey density are highest. Areas where lionfish 
are found may reflect not only favorable habitat 
for lionfish but also for native predators. 
This explanation could also apply to Pulley 
Ridge. The effect of lionfish has not been docu- 
mented previously for a habitat type such as 
grouper pits. These pits are essentially the only 
feature on the ridge with enough structural com- 
plexity to provide suitable habitat for both large 
predators and small reef fish. If high abundanc- 
es of fish are actively recruiting to these pits, it 
is conceivable that an effect from lionfish would 
not be observed. An alternative explanation for 
the lack of a lionfish effect could be the length 
of time since lionfish have colonized the loca- 
tion. In the Albins (2013) study, during which a 
negative effect from lionfish was observed, data 
were collected 4 years after the presence of li- 
onfish had been confirmed. In contrast, Elise et 
al. (2015) collected data just 1 year after lionfish 
were first sighted, and we began collecting data 
at Pulley Ridge just 2 years after lionfish were 
detected. 
Red grouper, through their manipulation of 
the substrate of their habitat form structural- 
ly complex pits that play an important role in 
the dynamics of fish communities. Overexploi- 
tation of red grouper because of its economic 
value could have negative effects on biodiver- 
sity (Coleman and Williams, 2002), especially 
In an area like Pulley Ridge where the pits are 
one of the only features providing habitat refuge for 
any number of fish species. Although Pulley Ridge is 
protected, because of its status as an HAPC, the regu- 
lations (ban on longlines, trawling, and anchoring) pri- 
marily protect coral and sessile invertebrates and not 
any of the 12 economically valuable fish species. Con- 
versely, hook-and-line fishing is still allowed in this 
otherwise protected area. The occurrence of hook-and- 
line fishing may explain why differences in abundance 
of red grouper were not observed inside versus outside 
the HAPC. 
The presence of fish in grouper pits is significant for 
fisheries management because a change in pit activity 
and numbers may indicate the presence and abundance 
of economically important fish. Over time, a change in 
pit density may indicate changes in fish populations 
and could be used to either evaluate health of a stock or 
the effectiveness of a fishery closure. Wall et al. (2011), 
for example, recorded an increase in the number and 
density of pits from 2006 to 2009 in Steamboat Lumps 
MPA by mapping habitat with acoustic sonar. Gather- 
ing additional information on the variety and number 
of fish associated with the pits could be used to evalu- 
ate their populations as well (Scanlon et al., 2005). The 
data reported here on pits uninhabited and habited by 
red grouper will be useful for management and could 
be used to assess the long-term health and status of 
the important fish communities found in grouper pits. 
