155 
National Marine 
Fisheries Service 
NOAA 
Fisheiy Bulletin 
^ estabiished in 1881 •«?. 
Spencer F. Baird 
First U.S. Commissioner 
of Fisheries and founder 
of Fishery Bulletin 
Age and grovuth of sheepshead (Mrchmargm 
pmbatocephatm} in Tampa Bay^ Florida 
Brent L. Winner (contact author)’ 
Timothy C. MacDonald’ 
Kimberly B. Amendoia* 
Email address for contact author: brent.winner@myfwc.com 
' Fish and Wildlife Research Institute 
Florida Fish and Wildlife Conservation Commission 
100 Eighth Avenue Southeast 
St. Petersburg, Florida 33701-5020 
2 Southeast Regional Office 
National Marine Fisheries Service, NOAA 
263 13th Avenue South, Suite 113 
St. Petersburg, Florida 33701 
Abstract— The sheepshead {Archos- 
argus probatocephalus) is common in 
coastal waters from the Chesapeake 
Bay to Texas in the United States 
and supports a viable recreational 
and commercial fishery throughout 
much of its range. Otoliths were ex¬ 
tracted from 2549 sheepshead col¬ 
lected from 1993 through 2009 in 
Tampa Bay, Florida, during routine 
sampling by the Fisheries-Indepen- 
dent Monitoring program of the Flor¬ 
ida Fish and Wildlife Conservation 
Commission. Sheepshead ranged in 
size from 107 to 524 mm fork length 
(FL). Age of sheepshead was esti¬ 
mated by counting annuli (opaque 
zones) in thin-sectioned sagittal oto¬ 
liths. Marginal-increment analysis 
of sheepshead from ages 1 to 6 indi¬ 
cated that a single opaque ring was 
formed on an otolith each year be¬ 
tween May and June. In Tampa Bay, 
sheephead reached a maximum age 
of 15 years. Males and females ex¬ 
perienced rapid growth through age 
6; growth rate decreased markedly 
thereafter. Although von Bertalanffy 
growth models were biologically sim¬ 
ilar between sexes, they were found 
to be statistically different (female 
[FL=419.1 (l-e-«-272(«ge-n-oo9))]. males 
[FL=422.5 (l-e-°-255(afie-^i-ii5))]). Tam¬ 
pa Bay sheepshead are typically 
smaller at a given age than those in 
more northern climates and not as 
long lived. Differences in regional 
growth models may be attributed to 
differences in mortality, ontogenetic 
shifts in habitat, genetic variation, 
or sampling design. 
Manuscript submitted 28 April 2016. 
Manuscript accepted 15 December 2016. 
Fish. Bull. 115:155-166 (2017). 
Online publication date: 31 January 2017. 
doi; 10.7755/FB.115.2.3 
The views and opinions expressed or 
implied in this article are those of the 
author (or authors) and do not necessarily 
reflect the position of the National 
Marine Fisheries Service, NOAA. 
The sheepshead {Archosargus pro¬ 
batocephalus) occurs from Nova 
Scotia (Gilhen et ah, 1976) to Bra¬ 
zil (Caldwell, 1965) and is common 
in coastal waters from Chesapeake 
Bay to Texas in the United States 
(Bigelow and Schroeder, 1953; Col¬ 
lette and Klein-MacPhee, 2002). Two 
subspecies of sheepshead have been 
reported within its U.S. range: A. 
p. probatocephalus, found along the 
Atlantic coast and into the Gulf of 
Mexico as far north as Steinhatchee, 
Florida, and A. p. oviceps, which oc¬ 
curs in the Gulf of Mexico from St. 
Marks River, Florida, to Campeche 
Bank, Mexico (Caldwell, 1965). Sub¬ 
specific distinction is based partly 
on pigmentation (size and number 
of vertical body bars) and meristic 
counts (lateral line scales, gill rak¬ 
ers, and dorsal fin spines and rays), 
both of which overlap considerably 
between the 2 subspecies (Caldwell, 
1965). Results of recent genetic anal¬ 
yses in which mtDNA of sheepshead 
from the Gulf of Mexico and South 
Atlantic indicated that a single pan- 
mictic population of sheepshead ex¬ 
ists within the range of this species 
from Texas through North Carolina 
(Anderson et ah, 2008; Seyoum et ah, 
in press). More detailed microsatel¬ 
lite analysis, however, has revealed a 
significant genetic break at the sub¬ 
species boundary in the Florida pan¬ 
handle (Apalachee Bay), providing 
genetic support for the validity of 2 
subspecies of sheepshead within its 
range in the United States (Seyoum 
et ah, in press). 
The combined recreational and 
commercial landings of sheepshead 
from the gulf coast of Florida be¬ 
tween 1990 and 2009 made up 19- 
44% of the total annual landings 
of sheepshead for all U.S. states in 
the Gulf of Mexico (National Marine 
Fisheries Service, Fisheries Statistics 
and Economics Division commercial 
annual landings statistics, available 
from website, accessed June 2014, 
and Marine Recreational Informa¬ 
tion Program time-series data, avail¬ 
able from website). The combined an¬ 
nual landings from the gulf coast of 
Florida peaked at 1755.6 metric tons 
in 1992; from 1996 to 2009, they av¬ 
eraged less than half that amount 
(841.3 metric tons/year) because of 
enactment in 1995 of a Florida con¬ 
stitutional amendment that limits 
