noon, less than 24 h after the presumed spawning 

 time. 



The spawning season extends from February 

 through July near Miami, based on our collec- 

 tions of planktonic eggs. Spawning may occur 

 within Biscayne Bay from late February through 

 early May but is confined to more offshore areas 

 later in the season. Biggest egg collections were 

 made about 4 km east of Miami Beach during 

 May and June. Martinez (1972) confirmed the 

 spawning season of scaled sardines by deter- 

 mining gonad indices and examining ovarian 

 maturation of adults collected throughout the 

 year from south Florida. 



Description of Larvae 



Body Shape 



Larvae were 2.4 mm at hatching. The head was 

 bent over the large, nearly spherical yolk sac. 

 Yolk was absorbed and the body axis straight- 

 ened during the next 12 h at 26° to 28°C. By 12 to 

 15 h after hatching, larvae were typically clupe- 

 oid (Figure 8A). They were elongate, thin larvae 

 averaging 4.4 mm at 15 h after hatching. The 

 gut was a long straight tube at this stage. Little 

 growth occurred during the first 3 days after 

 hatching. Thereafter, growth was rapid and 

 temperature-dependent (Saksena et al., 1972). 

 Larvae retained the typically elongate and rodlike 

 shape until they transformed to juveniles when 

 they became deeper bodied and laterally com- 

 pressed. Proportional measurements of larvae 

 in relation to standard length are given in 

 Table 1. 



FISHERY BULLETIN: VOL. 72, NO. 4 



Yolk Absorption and Gut Differentiation 



Absorption of the nearly spherical yolk mass 

 in newly hatched larvae was rapid at 26° to 

 28°C. The oil globule was located ventrally and 

 just posterior to the middle of the yolk mass in 

 newly hatched larvae (Figure 8A). By 48 h after 

 hatching the yolk sac and oil globule had been 

 absorbed, and larvae were actively feeding. The 

 gut was a straight tube at 15 h after hatching 

 (Figure 8A), but a distinct foregut and hindgut 

 were present at 2 days (Figure 8B). By 4 days 

 (at about 5.0 mm) the hindgut appeared to be 

 composed of a series of adjacent muscular rings, 

 typical of clupeid larvae. 



Total Length and Standard Length 



Standard length was used to examine develop- 

 ment of scaled sardine larvae with respect to 

 other morphometric data. The relation between 

 standard length and total length (Table 1, Figure 

 1) was not linear over all sizes of larvae that 

 were available. Standard length decreased rela- 

 tive to total length as larvae grew. Standard 

 length was about 97'7f TL for larvae between 4 and 

 8 mm TL but decreased to 857c TL for larvae be- 

 tween 8 and 25 mm TL. The ratio averaged about 

 83% TL for individuals longer than 25 mm TL. The 

 observed decrease between 8 and 25 mm TL was 

 related to development of the caudal fin, particu- 

 larly notochord flexure and hypural plate de- 

 velopment. 



Preanus Length 



Preanus length averaged 83% SL at 15 h after 



Table 1. — Summary of relationships between total lengths (TL) and standard lengths (SL), and proportional measurements relative to 

 standard lengths for larvae used to describe Harengulajaguana development. Proportions are from data fitted by eye to relationships in 

 Figures 1 to 5. 



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