315 
Abundance, growth, and mortality 
of young-of-the-year pinfish, 
Lagodon rhomboides, in three 
estuaries along the gulf coast 
of Florida 
Abstract .—Fixed-station and ran- 
dom-sampling data from 1989-94 were 
used to examine spatial and temporal 
patterns in abundance and size struc- 
ture of young-of-the-year (YOY) pinfish, 
Lagodon rhomboides , in three Florida 
estuaries. Young-of-the-year pinfish first 
appeared at shallow- water (<1.4 m) seine 
stations in November in Choctawhat- 
chee Bay (Florida Panhandle), and in 
December in Tampa Bay and Charlotte 
Harbor, both along the southwest Florida 
peninsula. Pinfish were caught at deep- 
water (>1.6 m) trawl stations within one 
month after their initial appearance at 
shallow-water (<1.4 m) sites in Choc- 
tawhatchee and Tampa bays. However, 
YOY were absent in the deep water of 
Charlotte Harbor until 1-3 months af- 
ter their first appearance in shallow 
water. Most YOY pinfish were caught 
in waters <3.5 m. Young-of-the-year 
pinfish in shallow-water areas were 
associated with bottom vegetation, 
mostly seagrasses, in all bays. Annual 
variation in YOY abundance was cor- 
related with variations in adult abun- 
dance in Tampa Bay and with tempera- 
ture in Charlotte Harbor. Instanta- 
neous growth rates were rapid (0.10 to 
0.26/month) and were similar to pub- 
lished rates for other Florida and gulf 
coast populations. Similar rates of to- 
tal instantaneous mortality (0.021 to 
0.023/day) were estimated for all bay 
populations. 
Manuscript accepted 3 December 1998. 
Fishery Bulletin 96:315-328 (1998). 
Gary A. Nelson 
Florida Marine Research Institute 
Department of Environmental Protection 
1 00 Eighth Avenue SE 
St. Petersburg, Florida 33701-5095 
E-mail address: nelson_ga@sellers. dep.state.fi. us 
Young-of-the-year pinfish, Lagodon 
rhomboides, play important ecologi- 
cal roles in the northeastern Gulf 
of Mexico as prey for fish (Carr and 
Adams, 1973; Seaman and Collins, 
1983) and as predators on a range 
of invertebrates, often to a degree 
where entire assemblages of macro- 
benthic fauna are affected (Young 
et al., 1976; Young and Young, 1977; 
Nelson, 1978). In addition, YOY pin- 
fish are an important link between 
primary and secondary production 
because they consume seagrasses 
(Stoner, 1982; Weinstein et al., 
1982; Montgomery and Targett, 
1992). 
Despite the ecological importance 
of pinfish, their population dynam- 
ics have been inadequately exam- 
ined. It is unknown if seasonal 
changes in abundance or move- 
ments occur throughout entire es- 
tuaries, if growth rates are similar 
among populations, or if abun- 
dances fluctuate annually because 
past studies have had limited spa- 
tial coverage (usually 1-4 seagrass 
sites were sampled in waters <2 m) 
and short sampling durations (<2 
yr)(Reid, 1954; Caldwell, 1957; 
Hellier, 1962; Hoese and Jones, 
1963; Cameron, 1969; Hansen, 
1970; Stoner, 1983). In addition, fac- 
tors that may influence year-class 
strength have not been examined, 
and mortality rates have not been 
estimated. 
In this study, I use two to six 
years of data to document seasonal 
changes in abundance, distribution, 
and movements within shallow- and 
deepwater areas to identify factors 
that may influence spatial and an- 
nual abundance and to estimate 
and compare growth and mortality 
rates among three estuarine popu- 
lations of YOY pinfish along the gulf 
coast of Florida, USA. 
Methods 
Young-of-the-year pinfish were 
studied in 1) Choctawhatchee Bay 
and Santa Rosa Sound (surface 
area: ca. 450 km 2 ), located in the 
western Florida Panhandle, 2) 
Tampa Bay (ca. 886 km 2 ), and 3) 
Charlotte Harbor (ca. 575 km 2 ), the 
latter two located on the gulf side 
of the Florida peninsula (Fig. 1). All 
three bay systems are characterized 
by average depths of <5 m, salini- 
ties of 0-36 ppt, freshwater inflow 
from rivers, and expanses of bottom 
vegetation, primarily seagrasses 
( Halodule wrightii and Thalassia 
testudinum), in shallow areas. Sea- 
sonal mean water temperatures 
range from 10 to 29°C in Choc- 
tawhatchee Bay and Santa Rosa 
