GRISWOLD and McKENNEY: LARVAL DEVELOPMENT OF SCUP 



Larvae 



Newly hatched larvae average 2.0 mm SL. The eyes 

 are not pigmented and the mouth is not functional. 

 The head is bent slightly over the elliptical yolk sac. 

 Yolk sac and oil globule are absorbed and gut dif- 

 ferentiation occurs between 48 and 72 h after hatch- 

 ing at 18°C. During this period the eyes become 

 pigmented, the mouth functional, and the larvae 



begin to feed. Larvae ranging in size from 2.0 to 18.7 

 mm are shown in Figure 1. 



Yolk Absorption and Gut 

 Differentiation 



At hatching the gut is a tube with a constriction at its 

 posterior end that extends to the ventral edge of the 

 finfold, but by 48 h (2.7 mm) a foregut and hindgut 



A DAY I 2.0 



B DAY 4 2.8 



C DAY 5 3.0 



F DAY 13 5.7 



G DAY 15 



7.3 



H DAY 17 9.4 



D DAY 6 3.4 



I DAY 21 14.9 



E DAY 9 4.2 J DAY 24 18.7 



FIGURE l.— Development of Stenotomus chrysops. Lengths (SL) are in millimeters. 



79 



