156 
Fishery Bulletin 115(2) 
the use of entangling nets and mandates the institution 
of minimum size and bag limits for recreational fisher¬ 
men (Munyandorero et al.^). Historically, more sheeps- 
head have been landed by recreational fishermen than 
commercial fishermen (70-95% of the combined annual 
landings during 1990-2009) along Florida’s gulf coast 
(Munyandorero et al.^). 
Growth has been described for larval and early ju¬ 
venile sheepshead from Florida waters (Parsons and 
Peters, 1989). Elsewhere, age and growth studies of 
juvenile and adult sheepshead have been conduct¬ 
ed in Georgia (Music and Pafford^), North Carolina 
(Schwartz, 1990), South Carolina (Wenner^), Louisiana 
(Beckman et ah, 1991), and northwest Florida (Dutka- 
Gianelli and Murie, 2001). Validated (Music and Paf- 
ford^) and unvalidated (Schv/artz, 1990) ages have been 
determined also from scales. However, Dutka-Gianelli 
and Murie (2001) reported that scales of sheepshead 
older than 3 years resulted in underestimated ages, and 
scales from sheepshead aged 2 or more years have been 
described as unreadable (Schwartz, 1990; Wenner^). 
Validated ages determined from otolith sections 
have been used to estimate von Bertalanffy growth 
parameters for sheepshead from Louisiana (Beckman 
et ah, 1991), South Carolina (Wenner^), and northwest 
Florida (Dutka-Gianelli and Murie, 2001). All 3 studies 
noted a high variability in size at age for sheepshead, 
reported von Bertalanffy growth parameters, and the 
predicted sizes at age varied considerably among the 3 
studies (Dutka-Gianelli and Murie, 2001). Each study 
relied almost exclusively on the fishery (commercial or 
recreational) for its samples. Beckman et al. (1991) in¬ 
dicated that because the gear types used were more 
apt to catch certain sizes of fish than others and be¬ 
cause fishermen occasionally sorted the catch before 
supplying the researchers with samples, the age and 
size structures of the sheepshead analyzed probably 
did not represent the overall population of sheepshead 
in Louisiana. Other researchers also have determined 
that reliance upon samples obtained only from the fish¬ 
ery can cause misrepresentation of the size distribu¬ 
tion and age structure of a population (Miranda et ah, 
1987; Hilborn and Walters, 1992; Wilson et ah, 2015). 
By design, we used multiple gear types and fisher- 
ies-independent methods to provide a more represen¬ 
tative sample across size and age classes of sheeps¬ 
head, therefore generating estimates of growth pa- 
1 Munyandorero, J., J. O’Hop, and C. Guenther. 2011. An 
assessment of the status of sheepshead in Florida waters 
through 2009. Florida Fish Wildl. Conserv. Comm., Fish 
Wildl. Res. Inst., IHR 2011-003, 137 p. Fish and Wildlife 
Research Institute, St. Petersburg, FL. [Available from web¬ 
site.] 
^ Music, J. L., Jr., and J. M. Pafford. 1984. Population dy¬ 
namics and life history aspects of major marine sportfishes 
in Georgia’s coastal waters, 382 p. Coast Res. Div., Georgia 
Dep. Nat. Resour., Atlanta GA. 
^ Wenner, C. 1996. Age and growth of sheepshead, Archo- 
sargus probatocephalus, from South Carolina waters with 
some preliminary management concepts, 17 p. S. Carolina 
Dep. Nat. Resour., Charleston, SC. 
rameters more representative of the true population. 
Otolith annuli (opaque zones) were validated to deter¬ 
mine age and growth parameters for sheepshead, and 
these estimates were then compared with those previ¬ 
ously reported for sheepshead from other geographical 
regions. 
Materials and methods 
Sheepshead were collected in Tampa Bay, Florida (Fig. 
1), a large estuary on the west coast of Florida that 
has an average depth of approximately 3 m and a 
maximum depth of 13 m (Comp and Seaman, 1985). 
All sheepshead v/ere captured from 1993 through 2009 
by the Fish and Wildlife Research Institute’s Fisher- 
ies-Independent Monitoring program during routine 
sampling with haul seines, trawls, gill nets, and tram¬ 
mel nets (Table 1). Haul seine and trawl samples were 
collected at both stratified-random and fixed sites; gill 
net collections were made at stratified-random sites. 
More detailed information about the sampling gears 
and protocols used by the Fisheries-Independent Moni¬ 
toring program can be found in Tremain and Adams 
(1995), Nelson et al. (1997), Nelson (1998), and Winner 
et al. (2010). Sheepshead were also taken as bycatch 
from trammel nets, which had been set on visually de¬ 
tected schools of striped mullet (Mugil cephalus), red 
drum (Sciaenops ocellatus), or common snook (Centro- 
pomus undecimalis). For each fish, we recorded stan¬ 
dard length (SL), fork length (FL), and total length 
(TL) to the nearest millimeter; sex; and total weight 
to the nearest 0.1 g before extraction of sagittal oto¬ 
liths, which were then rinsed, cleaned, and stored dry 
for further examination. 
Sex ratios of sheepshead were compared with a hy¬ 
pothetical 1:1 sex ratio by using the G-test (Sokal and 
Rohlf, 1981). Length distributions also were compared 
between sexes by using the Kolmogorov-Smirnov (KS) 
2-sample test (Proc Nparlway procedure in SAS^ soft¬ 
ware, vers. 5.1 (SAS Institute Inc., Cary, NC). Linear 
regression for all sheepshead collected was used to 
calculate sex-specific length-length and length-weight 
relationships (Proc Reg procedure in SAaS software) for 
untransformed and transformed (logio) data, respec¬ 
tively, and these relationships were compared through 
analysis of covariance (ANCOVA; Snedecor and Co¬ 
chran, 1967). Data from all fish collected were pooled 
when slopes and intercepts for sex-specific regressions 
were not significantly different. All significance testing 
was conducted at P<0.05. 
Three or four thin (-0.5 mm) transverse sections 
were cut at or adjacent to the core of the left sagitta 
with a Buhler Isomet low-speed saw equipped with a 
diamond blade; a right sagitta was sectioned when the 
left sagitta was missing or had been damaged. Oto- 
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the National Marine Fisheries Service, NOAA. 
