Harter et al.: Fish assemblages associated with grouper pits in the Gulf of Mexico 
429 
A 120 
8 _ioo 
-§ 3| 80 
§ i? 
-g ® 60 
a "2 
40 
2 E 
® =- 20 
< 
0 
I ^ 
E « 60 
B ioo - 
P0.0001 
C 
P=0.006 
80 - 
be 
ill 
a 
ib 
1 60 - 
a 
s i 
40 - 
20 - 
b 
0 - 
2012 2013 2014 
No Red Lionfish Both 
predator grouper only predators 
only 
D 200 
150 
100 
50 
0 
No protection 
Main Off main Central West 
ridge ridge basin ridge 
Figure 6 
Average abundance measured as number of individuals of small benthic fish, in- 
cluding cardinalfish ( Apogon spp.), damselfish ( Chromis spp.), small sea basses 
(Serranidae), wrasses ( Halichoeres spp.), and parrotfish (Labridae), associated with 
grouper pits surveyed during 2012-2015 off southwestern Florida, shown by the 
factor used to compare fish assemblages at pits: (A) year, (B) predator presence 
or absence, (C) inside or outside Pulley Ridge Habitat Area of Particular Concern 
(HAPC), and (D) region. Predators included the red grouper ( Epinephelus morio) 
and species of lionfish ( Pterois spp.). P-values are given for the results from one- 
way analysis of variance. Statistically significant differences are noted with differ- 
ent letters (a-c). Error bars indicate standard errors of the mean. 
' small and schooling fish through predation, possibly- 
confounding other results observed. The results of tests 
! with one-way AN OVA indicate that the presence of 
scamp did not have an effect on average abundances of 
either small fish (P=0.442) or schooling fish (P=0.244). 
Discussion 
Grouper pits inhabited by red grouper were observed 
to have greater species diversity and fish abundances 
compared with the levels observed at pits not inhab- 
ited by red grouper. These higher levels likely occurred 
because pits with red grouper are actively maintained, 
! with the resident grouper of a pit using its fins and 
mouth to keep the pit scoured down to the rock ledges, 
i The structural complexity of a pit remains intact, pro- 
viding habitat for other fish species. Once a pit loses its 
grouper (to fishing capture in fisheries or for another 
reason), the pit begins to fill in with sediment, and 
the exposed ledges are covered. Average abundances of 
both small, benthic species and larger, managed spe- 
cies were significantly higher in pits with a red grou- 
per present than in those with no predator. Some of the 
most abundant taxa in pits with red grouper present 
were the striped grunt, bonnetmouths, the school bass, 
cardinalfish, damselfish, and anthiids. Coleman et al. 
(2010) also observed higher species diversity in actively 
maintained grouper pits in the Steamboat Lumps and 
Madison-Swanson MPAs, which are 358 km north of 
Pulley Ridge. They found the most common species ob- 
served in those pits were the yellowtail reeffish, tom- 
tate ( Haemulon aurolineatum), the vermilion snapper 
( Rhomboplites aurorubens), the roughtongue bass ( Pro - 
notogrammus martinicensis), and a scad ( Decapterus 
sp.). 
An unusual observation from this study is the lack 
of a negative effect from lionfish on fish assemblages 
in the grouper pits that were analyzed. Most studies 
that have examined the effect of the invasion of lion- 
fish on native fish species have been conducted in shal- 
low water and have reported that lionfish adversely af- 
fect indigenous fish species (Albins and Hixon, 2008, 
2013). In a study that is analogous to our work and 
