420 
Fishery Bulletin 115(3) 
depths of 50-120 m) to alleviate fishing pressure on 
aggregations of gag ( Mycteroperca microlepis ). Grouper 
pits at Steamboat Lumps consist of carbonate rocks 
that have been scoured out from a thick veneer of 
carbonate-derived sediment. The pits are on average 
5-6 m in diameter but can become as large as 25 m in 
diameter and 1-2 m deep with a density of about 250 
pits/km 2 (Scanlon et al., 2005; Coleman et al., 2010; 
Wall et al., 2011). Pits in the Madison-Swanson MPA 
differ in their level of relief; some have a thin veneer 
of carbonate-derived sediments and some have more 
relief (Coleman et al., 2010). 
Our study area was at Pulley Ridge, a mesophotic 
coral ecosystem (MCE) in the northeastern Gulf of 
Mexico, which has large populations of red grouper and 
a high density of grouper pits. This geological feature 
is a carbonate ridge that extends for nearly 300 km 
along the southwestern shelf of Florida and lies about 
250 km west of the Florida coastline (Hine et al., 2008). 
The southern end of Pulley Ridge supports an MCE at 
depths of 60-100 m and covers an area of -600 km 2 
(Fig. 1; Jarrett et al., 2005; Cross et al. 3 ; USGS 4 ; Hine 
et al., 2008; Reed, 2016). Mesophotic coral ecosystems 
are characterized by the presence of light-dependent 
corals and their associated communities, and Pulley 
Ridge is the deepest MCE on the U.S. continental shelf 
(Halley et al. 5 ). The hard-bottom substrate along this 
ridge consists of rock and coral pavements and cement- 
ed conglomerates of carbonate rubble and cobble rock 
(5-15 cm in diameter) that provide habitat for herma- 
typic corals (primarily Agaricia spp., great star coral 
[Montastraea cavernosa ], and Madracis spp.), macroal- 
gae, sponges, and a large variety of species of tropical 
fish (Phillips et al., 1990; Halley et al. 5 ; Reed, 2016). 
The Pulley Ridge Habitat Area of Particular Concern 
(ELAPC) was established in 2005 by the Gulf of Mexico 
Fishery Management Council 6 to provide protection 
from bottom longlines and trawls. Hook-and-line fish- 
ing, however, is still allowed. The established HAPC 
provides protection for 348 km 2 , an area that is rough- 
ly half the total MCE area (Reed, 2016). 
Structural complexity has often been shown to posi- 
3 Cross, V., D. C. Twichell, R. B. Halley, K. T. Ciembronowicz, B. 
D. Jarrett, E. S. Hammar-Klose, A. C. Hine, S. D. Locker, and 
D. F. Naar. 2005. GIS compilation of data collected from 
the Pulley Ridge deep coral reef region. U.S. Geol. Surv. 
Open-File Rep. 2005-1089. [Available from website.] 
4 USGS (U.S. Geological Survey). 2005. Recently discovered 
reef is deepest known off continental U.S. ScienceDaily, 5 
January 2005. [Internet press release available from web- 
site.] 
5 Halley, R. B., V. E. Garrison, K. T. Ciembronowicz, R. Ed- 
wards, W. C. Jaap, G. Mead, S. Earle, A. C. Hine, B. Jarret, 
S. D. Locker, et al. 2003. Pulley Ridge — The United States’ 
deepest coral reef? In U.S. Geological Survey Greater Ev- 
erglades Science Program: 2002 biennial report. U. S. Geol. 
Surv. OFR-03-54, 153-154 p. [Available from website.] 
6 Gulf of Mexico Fishery Management Council (GMFMC). 2005. 
Essential Fish Habitat Amendment 3. Addressing essential 
fish habitat requirements, habitat areas of particular con- 
cern, and the adverse effects of fishing on fishery manage- 
ment plans of the Gulf of Mexico. 
tively influence abundance and diversity of fish spe- 
cies (McClanahan, 1994; Ohman and Rajasuriya, 1998; 
Gratwicke and Speight, 2005; Harter et al., 2009). Most 
of Pulley Ridge is a low relief, low rugosity, rock and 
rubble habitat. The highest densities of fish reside on 
2 biologically derived habitat features that provide 
more structural complexity: mounds of rock rubble and 
cobble created by sand tilefish ( Malacanthus plumieri) 
and grouper pits (Halley et al. 7 ). The grouper pits are 
large enough (8-15 m in diameter and 1-2 m deep) to 
be visible in high-resolution bathymetric images col- 
lected with a multibeam sonar during a research cruise 
in September 2011 (NOAA 8 ), and up to 340 pits/km 2 
are visible in those images. Approximately 90 species 
of fish, both shallow-water and deepwater species, have 
been observed on Pulley Ridge (Jaap et al., 2015). The 
fish communities of Pulley Ridge have been character- 
ized previously, but communities associated with the 
grouper pits specifically have not. 
Species of lionfish ( Pterois spp.) first were discov- 
ered on Pulley Ridge during submersible dives in 2010 
(Reed and Rogers 9 ) when 6 fish were observed. Since 
then, exponential increases in the abundance of this 
population of lionfish have been observed (Andradi- 
Brown et al., 2016). It is unknown at this time wheth- 
er red lionfish (P. volitans), devil firefish (P. miles), or 
both species exist at Pulley Ridge. At this time, posi- 
tive identification can be achieved only through genet- 
ic analysis; therefore, lionfish were identified only to 
genus level for this study. The invasion of lionfish is 
regarded as one of the most successful colonizations of 
a marine species ever documented (Albins and Hixon, 
2008; Green and Cote, 2009; Albins, 2013). Lionfish 
first were recorded in waters of the Atlantic Ocean in 
the mid-1980s, but their range has expanded to include 
the Gulf of Mexico, Caribbean, and much of the tropi- 
cal and subtropical western Atlantic Ocean (Schofield, 
2009, 2010). Over the years, densities of lionfish in the 
western Atlantic Ocean have expanded rapidly to the 
point that they are nearly 5 times more abundant in 
the invaded range (Green and Cote, 2009) than in the 
Pacific Ocean (Kulbicki et al., 2012). High individual 
growth and reproductive rates (Morris and Whitfield, 
2009) have contributed to the rapid increase of the 
population in the western Atlantic Ocean. Many stud- 
7 Halley, R., G. R Dennis, D. Weaver, and F. Coleman. Halley, 
R., G. P. Dennis, D. Weaver, and F. Coleman. 2005. Part 
II: characterization of the Pulley Ridge coral and fish fau- 
na. Final report to the National Oceanic and Atmospheric 
Administration Coral Reef Conservation Grant Program, 25 
p. [Available from website.] 
8 NOAA. 2011. Multibeam sonar bathymetry data collected 
aboard Nancy Foster (NF-11-09-CIOERT). NOAA National 
Centers for Environmental Information. [Available from 
website.] 
9 Reed, J. K., and S. Rogers. 2011. Final cruise report. Flor- 
ida Shelf-Edge Expedition (FLoSEE), Deepwater Horizon oil 
spill response: survey of deepwater and mesophotic reef eco- 
systems in the eastern Gulf of Mexico and southeastern Flor- 
ida. R/V Seward Johnson and Johnson-Sea-Link submersible, 
July 9-August 9, 2010, 16 p. [Available from website.] 
