773 
Abstract.-Sagittal otoliths were 
used to determine age and growth of 605 
larval and juvenile Atlantic croaker, 
Micropogonias undulatus, collected in 
the Middle Atlantic Bight and estua- 
rine waters of Virginia. This study is the 
first to use age-based analysis for young 
Atlantic croaker collected in this region. 
A Laird-Gompertz model (^=0.95) was 
used to describe the growth of Atlantic 
croaker up to 65 mm standard length 
(SL) and 142 days (t): SL [t) = 2.657 exp 
14.656 [1-exp (-0.008 It )]); where SL {t) = 
standard length at day t. Spatial and 
temporal patterns in the size and age of 
Atlantic croaker showed a pattern of in- 
shore immigration from offshore spawn- 
ing grounds, and faster early-season 
growth compared with late-season 
growth. Back-calculated hatching dates 
of Atlantic croaker collected in Virginia 
estuaries indicated a protracted spawn- 
ing period over 8 months, from early 
July 1987 to early February 1988, with 
at least 82% of spawning occurring from 
August to October. Regression analysis 
indicated that early-spawned larvae 
(July through August) grew more than 
39% faster than late-spawned larvae 
(September through February). Lapillar 
and sagittal otoliths were compared 
with light microscopy; ages were under- 
estimated with lapillar otoliths, which 
were particularly inadequate in deter- 
mining the age of older juveniles. The 
relation between SL and sagittal otolith 
maximum diameter was best described 
by a fourth order polynomial (r 2 =0.99) 
and faster-growing Atlantic croaker 
had larger otoliths ( 12%) than the same 
size slower-growing fish. 
Manuscript accepted 12 March 1997. 
Fishery Bulletin 95:773-784 ( 1997). 
Age and growth of larval and 
juvenile Atlantic croaker, 
Micropogonias undulatus, 
from the Middle Atlantic Bight 
and estuarine waters of Virginia 
Stephen W. Nixon* 
Cynthia M. Jones 
Applied Marine Research Laboratory, Department of Biological Sciences 
Old Dominion University 
Norfolk, Virginia 23529 
* Present address: Department of Zoology 
PO Box 761 7, North Carolina State University 
Raleigh, North Carolina 27695 
E-mail address (for S W. Nixon):swnixon@umty.ncsu.edu 
Atlantic croaker, Micropogonias un- 
dulatus, range from New York to 
Florida and along the western and 
northern Gulf of Mexico (Ross, 1988; 
Atlantic States Marine Fisheries 
Commission, 1993). Historically, 
Atlantic croaker have ranked as one 
of the top five species in the com- 
mercial catch of finfishes in the 
middle Atlantic region (McHugh 
and Conover, 1986), although re- 
cruitment is highly variable in the 
species. In Virginia, annual com- 
mercial landings have varied by as 
much as threefold and have appar- 
ently declined overall since 1937 
(Chesapeake Bay Program, 1988). 
Similarly, recreational landings 
have varied by as much as twofold 
over two years (U.S. Department of 
Commerce, 1991). 
In species with substantial an- 
nual recruitment variability, change 
in the survival rate of prerecruits 
(larvae and juveniles) is a key fac- 
tor in determining adult abundance 
(Houde, 1987). Determination of 
survival rates of prerecruits relies, 
in part, on daily age and growth 
information (Jones, 1992), and al- 
though otolith daily increment 
analysis has become common prac- 
tice (Jones, 1992), there are few 
published age and growth studies 
on the early life history of Atlantic 
croaker. Furthermore, there are no 
age-based estimates of growth for 
larval and juvenile Atlantic croaker 
for the Middle Atlantic Bight (MAB: 
shelf waters from Long Island, NY, 
to Cape Hatteras, NC) and estua- 
rine waters of Virginia. Comparable 
age-based studies on the early life 
history of Atlantic croaker have con- 
centrated on larvae collected in 
coastal waters south of Cape Hat- 
teras, North Carolina (Warlen, 1982), 
or the northern Gulf of Mexico (Co- 
wan, 1988). 
North Carolina larvae (Warlen, 
1982), collected south of Cape 
Hatteras at Beaufort Inlet, show a 
twofold decline in length-at-age be- 
tween early- and late-season collec- 
tions. Likewise, Cowan (1988) 
shows a similar slow growth rate for 
late-season larvae collected in the 
northern Gulf of Mexico. Warlen’s 
(1982) back-calculated hatching 
dates indicate a broad spawning 
season from September to February, 
with peak spawning in October and 
November. On the basis of the pat- 
tern of progressive increase in mean 
size and age from the shelf to the 
estuary and on the basis of seasonal 
