HOUDE, RICHARDS, and SAKSENA: EGGS AND LARVAE OF SCALED SARDINE 



Table 2. — Distribution of myomeres relative to other body parts for Harengula jaguana larvae. 



part until larvae were about 16 mm. Pectoral 

 fin buds were present at hatching (Figure 8A), 

 but no other fins were developed at this stage. 

 An opaque area in the fin fold was the first indi- 

 cation of median fin development. Rayed fins 

 developed in the following sequence: dorsal, cau- 

 dal, anal, pelvics, pectorals. Fin rays first develop 

 as cartilaginous structures; thus, the sizes of 

 larvae at which full complements are present 

 may be smaller than the sizes at which rays are 

 fully ossified. Tables 3 and 4 summarize fin de- 

 velopment sequence of scaled sardine larvae, 

 and details are discussed in the osteological 

 development section. 



Median fin development usually was com- 

 pleted at 16.0 mm. Dorsal fin rays first ap- 

 peared between 7.0 and 7.5 mm. A full com- 

 plement of 17 to 19 rays was present at 14.0 

 to 17.0 mm. Principal caudal rays were first seen 



at 7.4 to 8.0 mm, and the full complement of 19 

 usually was attained at 10.0 mm. Some specimens 

 as small as 8.5 mm had the full complement of 

 principal caudal rays; a few specimens did not 

 have a full complement until they were longer 

 than 11.0 mm. Secondary caudal rays developed at 

 10.8 to 12.8 mm, and the full complement of 8 or 9 

 dorsal and 7 ventral secondary caudal rays was 

 present at 16.5 to 19.0 mm. Notochord flexure, 

 which occurs during caudal fin development, 

 began at the same size that principal caudal rays 

 first developed. Anal fin rays usually began to 

 develop at 9.0 to 9.3 mm, but two specimens 8.5 to 

 9.0 mm had some anal rays. A full complement of 

 17 or 18 anal rays was present at 13.0 to 15.0 mm. 

 Although principal caudal and anal fin rays began 

 to develop after dorsal fin rays, the dorsal was the 

 last median fin to attain its full ray complement. 

 Paired fins began to develop after median 



Table 3. — Summary of fin development sequence in larvae of Harengula jaguana. 



'Rays were present at the tabulated lengtfis. but not necessarily ossified at those sizes. 



1111 



