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Fishery Bulletin 107(3) 
ing microscope. All larvae were photographed on their 
left sides in the sagittal plane, and a fine-point needle 
was used to position larvae as necessary. Microscopes 
were equipped with high-resolution digital cameras 
(Sony DSC-FS17, San Diego, CA), and photographs 
were recorded as uncompressed files in tagged image 
file format (TIFF) at 6 megapixels. For calibration, a 
0.01-mm micrometer scale bar was photographed for 
each larval series and for both microscopes. 
Image analysis 
Larvae and selected anatomical features were mea- 
sured and analyzed by using SigmaScan Pro 5.0 image 
analysis software (SPSS Science, Chicago, IL). All mor- 
phometric measurements listed below were recorded 
to the nearest 0.001 mm and calibration errors were 
maintained at less than 1 pm (<0.1% of 1 mm). The 
total length (TL) and standard length (SL) of larvae was 
measured along lines parallel to the longitudinal axis 
of the fish (Snyder 1983). 
Body depth — The distance, perpendicular to the lon- 
gitudinal axis of the body from the insertion of the first 
dorsal spine to the ventralmost point of the body. For 
yolksac larvae, the distance perpendicular to the longi- 
tudinal axis of the body from the dorsal crest through 
CD 
Figure 1 
Size-frequency histograms of rotifer cultures used to 
feed larval Florida pompano (Tracliinotus carolinus). 
Stock cultures of rotifers (Brachionus plicatilis) were 
obtained from (A) Aquaculture Center of the Florida Keys 
(ACFLK, Marathon, FL) in 2004 and (B) Oceans Reefs 
and Aquariums (ORA, Fort Pierce, FL) in 2005. 
the midpoint of the yolk to the ventralmost point of 
the body. 
Head length — The distance, parallel to the longitu- 
dinal axis of the head, from tip of snout to the edge of 
the operculum. 
Eye diameter — The distance, parallel to the longi- 
tudinal axis of the head, from anteriormost to posteri- 
ormost points of bony orbit. 
Yolksac length — The distance, parallel to longitudi- 
nal axis of the body, from anteriormost to posteriormost 
points of the yolk sac. 
Yolksac depth — The distance, perpendicular to the 
longitudinal axis of the body, from ventralmost to dor- 
salmost points of yolk sac. 
Oil globule diameter — The distance, parallel to 
longitudinal axis of the body, from anteriormost to pos- 
teriormost points of oil globule. 
Length of upper jaw — The length of the premaxil- 
lae and maxillae to the point of articulation with the 
dorsal process of the dentary. 
Length of lower jaw — The length of the dentary to 
the point of articulation with the angular and maxillae. 
At the time of measurement, observations of larval 
development state were recorded to identify the chrono- 
logical sequence of events. The following critical periods 
were noted when first observed: 1) hatching; 2) mouth 
formation; 3) body pigmentation; 4) eye formation and 
pigmentation; 5) stomach and digestive tract forma- 
tion; 6) first feeding; 7) yolk exhaustion; 8) oil globule 
exhaustion; 9) diet transition from rotifers to Artemia 
spp.; and 10) metamorphosis. Completion of the larval 
stage and metamorphosis was defined as the point when 
the axial skeleton is ossified and fish acquire the ana- 
tomical and morphological characteristics of juveniles. 
The relationship between TL and age; SL and age; 
and mouth gape and age were plotted separately for 
each larval rearing trial. Total and standard length 
data of larvae were fitted to a simple curvilinear equa- 
tion (i.e., y=a+ b xx° 5 ). The comparison between these 
plots allowed assessment of somatic growth pattern 
through time. Repeated-measures analysis of variance 
was then used to statistically compare growth rates 
among rearing trials. To normalize observations and 
stabilize the variance, data were logarithmically trans- 
formed before statistical analysis. Tukey’s test was used 
to determine if significant differences existed among 
treatment means. Differences were considered signifi- 
cant at P<0.05. The general linear model function in 
SigmaStat 3.0 (SPSS Science, Chicago, IL) was used 
for all analyses. 
Regression equations were calculated for total and 
standard length, yolk volume, and oil globule volume for 
larvae cultured from each spawn. Yolk volume was de- 
termined by using the equation for a prolate spheroid: 
Yolk volume = 
4/3 ji [ yolk-sac length ] [yolk-sac depth] 2 . (1) 
Oil globule volume was determined by using the equa- 
tion for a sphere: 
