Riley et al.: Development and growth of hatchery-reared larval Trachinotus carolmus 
321 
Oil globule volume = 
4/3 jt [ oil globule diameter /2] 3 . (2) 
Length and volume data were then plotted against 
age. The curvilinear equation, y-a + by-x^ 1 , was 
fitted to the yolk and oil globule volume data and 
plotted with 95% confidence limits. 
The mouth gape was determined by using length 
measurements of the upper and lower jaws and 
the Law of Cosines equation for a triangle with 
two known sides and an angle between them: 
a 2 = b 2 + c 2 - 2 be cos a, (3) 
where a = mouth gape; 
b = upper jaw; 
c - lower jaw; and 
a = angle that forms the degree of mouth 
opening. 
Calculations were based on the assumption that 
during active feeding the mouth of larvae opens to 
an angle ranging from 90° to 120° to capture prey 
(Shirota, 1970). Optimal prey sizes were estimated 
at 30% and 50% of mouth gape for larvae (Yasuda, 
1960; Shirota, 1970; Hunter and Lasker, 1981; 
Cunha and Planas, 1999). 
Results 
During each 20-day trial, production of postmeta- 
morphic juvenile Florida pompano ranged from 
1.5 to 5.0 fish/liter. Although water temperature 
is an important factor governing growth, there 
was no significant difference among any of the 
water quality parameters measured among rear- 
ing trials (P=0.67). In the first rearing trial, dis- 
solved oxygen was 5.7 ±0.2 mg/L (mean ± SE), 
temperature was 25.5 ±0.2°C, and salinity was 
34.9 ± 0.6 g/L. In the second rearing trial, dis- 
solved oxygen was 5.6 ±0.2 mg/L, temperature 
was 25.5 ± 0.2°C, and salinity was 34.8 ±0.5 g/L. 
In the third rearing trial, dissolved oxygen was 
5.7 ±0.1 mg/L, temperature was 25.0 ±0.6°C, and 
salinity was 34.5 ±0.6 g/L. 
Eggs collected from each spawning event were 
uniform in shape and appearance. Fertilized eggs 
were 0.99 ±0.04 mm in diameter and contained 
a single oil globule (Fig. 2A). Newly hatched larvae 
were transparent, small (TL = 2.6 ±0.4 mm), and not 
well developed (Fig. 2B). As typical of carangids, lar- 
vae hatched with large, elongate yolk sacs extending 
beyond the head and along the ventral region of the 
head and gut. A single oil globule was situated at the 
posterior end of the yolk sac. At hatching, the lower 
and upper jaws, as well as the digestive tract, were not 
fully developed. Pigmented eyes and functional mouth 
parts had formed by the end of two DAH when the 
larval swimming pattern became stronger and feed- 
ing behavior was first observed. Melanophores were 
observed forming along the head and dorsal surface 
of the body at two DAH. The stomach and a primitive 
intestine were observed forming at two DAH, and the 
intestine had connected with the anus at three DAH. 
Rotifers and algae were first observed in the stomachs 
of larvae at three DAH. Larvae had exhausted yolk 
reserves at three to four DAH and the remaining oil 
globule at four to five DAH and were completely tran- 
sitioned to exogenous feeding at five DAH (Fig. 3; Fig. 
4A). Larvae at seven DAH exhibited a fully formed 
