Collins and McBride: Spatially explicit life-history dynamics of a protogynous reef fish 
237 
o 
o 
CO 
<® offshore (transect n= 54) 
O nearshore (transect n- 229) 
* f 
• Male (n=92) 
B 
v Transitional (n=61) 
O Female (n= 342) 
• l i 
- 
5 v * 
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5 
O £ 
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10-19 
20-29 30-39 
Depth (m) 
Figure 3 
Mean observed densities and fork lengths (FL) for all sex 
phases of hogfish ( Lachnolaimus maximus) as observed over 
increasing depths (by 10-m intervals). (A) Densities recorded 
during visual transects. Calculations were not performed for 
sites deeper than 45 m because of limited survey time, and 
are designated by *. (B) Mean fork lengths for each sex phase, 
as determined by histological examination. The dotted line 
separates nearshore and offshore data. Error bars indicate 
standard error of the mean. 
10-m intervals did not reveal significant differ- 
ences for density or size distribution (Fig. 3, A 
and B). 
Hogfish aggregations varied in number and sex 
ratio. Females were most common and were re- 
corded during 206 out of 283 transects (mean 
n = 6), whereas males were recorded during only 
103 out of 283 transects (mean n= 1.5). As many as 
25 individuals were recorded during a single tran- 
sect. The maximum number of females observed 
during a transect was 23, and the maximum 
number of males observed was 4. Occasionally, 
more than four males were noted at a site beyond 
the boundaries of the transect, but typically, if 
males were observed, it was more common to see 
only one or two during the survey. When both 
sexes were present (n = 94 transects), the larg- 
est fish observed were always males. Sex ratio 
(males:females) ranged from 0.0 to 1.0 (Fig. 4), 
with a mean of 0.14 (overall), 0.14 (nearshore), and 
0.20 (offshore). Sex ratio showed no relationship 
to depth (P= 0.90) or season (P=0.99). 
Visual surveys were completed between Novem- 
ber 2005 and June 2007, when bottom tempera- 
ture, dissolved oxygen, and salinity were mea- 
sured within the following ranges: 15.7-31.2°C, 
6. 0-9. 6 mg/L, and 29-36 PSU, respectively. 
Life history 
Life history analyses supported visual survey 
observations, with hogfish size and age positively 
related to depth. Ages were assigned to 622/653 
fish (95%), and ranged from 0 to 19 years old. 
Collection depth data were available for 92% of 
all harvested hogfish (601/653). Hogfish collected 
nearshore (71=264) ranged from 102 to 492 mm 
FL and from 0 to 8 years old; those from offshore 
(ti = 337) ranged from 319 to 774 mm FL and from 
2 to 19 years old (Fig. 5). Fish at a common age 
were larger offshore, indicating that faster grow- 
ing fish occur in deeper water (Fig. 6). 
Reproductive classes were assigned to 472 
aged individuals. As expected for a protogynous 
hermaphrodite, the majority of hogfish were female 
(classes 1-4; n = 342). The remaining individuals were 
classified as transitional or immature males (class 5 or 
6, respectively; ti = 61) or mature males (classes 7-10; 
72 = 92). Size and age at 50% maturity for females were 
151.6 mm FL and 0.9 years. It is assumed that females 
completed maturation nearshore because immature 
females were not observed at depths >22 m. 
Females were smaller and younger nearshore (means: 
246 mm FL, 2.3 yr; ti= 159) than offshore (means: 479 
mm FL, 6.7 yr; 72 = 161) (PcO.OOOl). Sex change oc- 
curred across a wide range of sizes (197-727 mm FL) 
and ages (1-11 yr) and was observed both nearshore 
and offshore. Median size and age at sex change were 
significantly less nearshore (327 mm FL; 2.8 yr; 72 = 15) 
than offshore (592 mm FL; 7.8 yr; 72 = 18) (PcO.OOOl) 
(Fig. 7). The smallest transitional fish collected off- 
shore was 449 mm FL. All fish >685 mm FL or older 
than 10.5 years were in the process of sex change or 
were already male. 
Discussion 
We identified distinct cross-shelf patterns in the 
presence and density of hogfish; both were greater 
nearshore. Hogfish were distributed widely, but not 
randomly. Across all depths sampled, their presence 
and density were greatest over complex, natural hard 
bottom habitats. In the Florida Keys, hogfish actively 
select habitat, preferring sandy rubble and gorgonian 
microhabitats (Munoz et al., 2010). 
