Collins and McBride: Spatially explicit life-history dynamics of a protogynous reef fish 
233 
Figure 1 
Study location in the central eastern Gulf of Mexico. Dive sites are indicated by 
dots (431 sites) and were surveyed for hogfish ( Lachnolaimus maximus) between 
2005 and 2007. Hogfish were harvested randomly from dive sites during scuba 
surveys. Bathymetry contours are isobaths and are labeled to 100 m; the 30-m 
isobath is bold and separates nearshore (<30 m) from offshore (>30 m) sites. 
Fishery regulations for hogfish 
were first implemented in 1994. 
The minimum size limit (305 mm 
FL) corresponded with the mini- 
mum length at sex change (Da- 
vis, 1976) and was established to 
protect spawning fish. However, 
concerns about the effectiveness 
of this size limit emerged when 
further research demonstrated 
that median size at sex change 
was significantly larger (-380 
mm FL; McBride et ah, 2008). 
Continual removal of the domi- 
nant male can impact the repro- 
ductive capacity of a population 
(Bannerot et al., 1987; Sluka and 
Sullivan, 1998). Under heavy 
fishing pressure, constant disrup- 
tion of hogfish spawning harems 
could be problematic because sev- 
eral months are required to com- 
plete sex change (McBride and 
Johnson, 2007) and new males 
have lower reproductive success 
(Munoz et al., 2010). A stock as- 
sessment in 2003 (Ault et al. 1 ) 
stated that hogfish were under- 
going overfishing in the U.S., 
but these findings were disputed 
because of concerns that catch 
and effort data were inadequate 
(Kingsley 2 ). Under such condi- 
tions, demographic data may 
provide the only basis for setting management refer- 
ence points (Brooks et al., 2010) and evaluating future 
monitoring strategies. 
Data were collected through cooperation with the 
spearfishing community, and revealed abrupt, cross- 
shelf patterns in hogfish demographics. These findings 
highlight interactions between fishing operations and 
the environment on reef fish populations, specifically 
demonstrating that sex change mechanisms can be 
spatially explicit and that refuges may exist for larger 
spawners that survive long enough to reach offshore 
habitats. 
1 Ault, J. S., S. G. Smith, G. A. Diaz, and E. Frank- 
lin. 2003. Florida hogfish fishery stock assessment. Final 
report to Florida Fish & Wildlife Conservation Commission, 
89 p. [Available from NOAA Southeast Fisheries Science 
Center, www.sefsc.noaa.gov/sedar/download/SEDAR6_RW4. 
pdf?id=DOCUMENT, accessed February 2011.] 
2 Kingsley, M. C. S., ed. 2004. The hogfish in Florida: 
Assessment review and advisory report. Southeast data and 
assessment review, 15 p. Prepared for the South Atlantic 
Fishery Management Council, the Gulf of Mexico Fishery 
Management Council, and the National Marine Fisheries 
Service. [Available at: http://www.sefsc.noaa.gov/sedar/ 
download/SEDAR6_SAR2_hogfishall.pdf?id= DOCUMENT, 
accessed February 2011.] 
Materials and methods 
Sampling design 
Visual observations and hogfish collections were made 
during scuba dives (to a depth of 69 m) in the central 
eastern Gulf of Mexico (Fig. 1). To investigate whether 
increasing depth and distance from shore affected hog- 
fish distribution and demographics, scuba surveys were 
allocated to sample a range of depths and were catego- 
rized as nearshore (<30 m) or offshore (>30 m). Thirty 
meters was chosen as the dividing point between the 
nearshore and offshore classification because many rec- 
reational divers do not exceed this depth on account of 
the reduced available bottom time and greater hazards 
associated with diving at deeper depths. Additionally, 
this 30-m depth corresponds roughly with a distance of 
40-50 km from land, beyond which travel becomes more 
costly in terms of travel time, fuel expense, and risks 
associated with adverse weather. Sites were also exam- 
ined by 10 -m depth intervals to identify whether there 
were finer scale effects of depth on hogfish distribution. 
Habitat was characterized into one of three major 
categories according to bottom type and relief: 1) natu- 
ral habitat of rugose hard bottom with a maximum 
vertical relief >0.5 m, typically limestone outcroppings 
