KENDALL: BLACK SEA BASS LARVAE 



notochord. Between 4 and 5 mm the anlage of 

 the base of the caudal fin starts to form ventral 

 to the notochord, just anterior to its tip (Figure 

 3A). By 5.5 mm the notochord is slightly up- 

 turned, the developing hypural region appears 

 bilobed and about nine primary caudal rays are 

 formed. The caudal fin at 6 mm has a rounded 

 homocercal outline and eight segmented prin- 

 cipal rays in the superior lobe and seven in the 

 inferior lobe (Figure 3B) ; the rays are branched 

 and some secondary procurrent rays are present. 

 At 8 mm the dorsal hypurals are slightly longer 

 than the ventral ones and the rays and raylets 

 are more clearly defined and approaching the 

 adult complement (Table 1). 



Anal Fin 



Between 2 and 5 mm there is an undifferen- 

 tiated finfold in the area of the anal fin. Between 

 5 and 6 mm, fin rays start to form in the anal 

 finfold between the vent and the most prominent 

 pigment spot on the ventral surface of the trunk 

 (Figure 3A). By 6 mm about six rays and one 

 anal spine are seen (Figure 3B). The finfold 

 posterior to the fin is reduced. By 7 mm the 

 three anal spines are formed. The second spine 

 is first to form and is most prominent through- 

 out development (Figure 3C), The third spine 

 forms as a ray; by 7 mm the spinous form is 

 apparent. The first spine is smaller than the 

 others and forms last at 6.5 mm. By 7 mm the 

 adult complement of seven anal rays is reached 

 and some are branched (Table 1). 



Dorsal Fins 



The undifferentiated dorsal finfold extends 

 from the nape to the caudal region at 4 mm. By 



5 mm the finfold becomes elevated about half- 

 way back on the body where fin ray development 

 begins (Figure 3A). Rays and spines develop 

 along the dorsal fin base and the dorsal finfold 

 posterior to the dorsal fin disappears between 

 5.5 and 6.5 mm. The anterior spines and poste- 

 rior rays develop at a smaller size than inter- 

 mediate fin elements. 



The first four dorsal spines are visible by 



6 mm. The second through fourth are longer 



and remain so. The first dorsal spine is about 

 half as long as the second. The second and third 

 spines are the same length at 6.5 but, by 10 mm, 

 the third has become 1.5 times longer than the 

 second. The fourth spine^ the longest, is slightly 

 longer than the third. The final complement 

 of 10 spines and 11 rays is attained by 8.7 mm 

 (Table 1). The rays are branched and seg- 

 mented by 8 mm (Figure 3C). 



Median Fin Supports 



Anterior interneurals and the interhemal sup- 

 porting the second anal spine ossify concurrently 

 at about 8.5 mm. By 10 mm most of the inter- 

 neurals and interhemals are formed. The an- 

 terior two interneurals fuse to support the first 

 two dorsal spines (Figure 8) . The first two anal 

 spines are supported by one interhemal, appar- 

 ently formed by fusion of two elements (Figure 

 8). 



Pelvic Fins 



Buds of the pelvic fins are seen on 4-mm lar- 

 vae. Fin rays form between 4 and 6 mm. Rays 

 and spines are first seen between 5 and 6 mm 

 (Figure 3B). At 8 mm the adult complement 

 of one spine and five rays has formed, with the 

 smooth spine two-thirds as long as the longest 

 ray (Table 1). 



Pectoral Fins 



Pectoral fin buds are present on the smallest 

 larvae (2.1 mm) examined. The early pectorals 

 change little until fin rays appear between 5 and 

 6 mm. By 6.5 mm the rays are mostly formed 

 and the adult complement of 18 or 19 rays is 

 reached by 9 mm (Table 1), 



Gill Rakers 



At 5 mm gill rakers appear as a few tubercles 

 on the gill arches. By 6 mm there are nine 

 rakers on the lower limb and none on the upper. 

 At 10.6 mm there are 4 rakers on the upper and 

 10 on the lower limb. The adult complement of 

 about 10 upper and 18 lower is reached in ju- 

 veniles. 



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