FISHERY BULLETIN: VOL. 82, NO. 1 



can be distinguished. The hindgut appears to be 

 muscular and remains a tube until between day 7 and 

 day 9 (ca. 4.0 mm), when a well-defined stomach 

 becomes apparent and the hindgut is relatively 

 shorter. 



Total Length and Standard 

 Length 



Larval growth appears to be gradual and continuous 

 with no well-defined changes in relative body propor- 

 tions. Apparent slight changes which are noticeable 

 after notochord flexion relate to a change in measure- 

 ment from an SL which is actually notochord length 

 to one which is a true SL. 



Snout Length 



As with eye diameter, there is considerable varia- 

 tion among individuals of the same size. At hatching 

 the snout length is 2.5% of SL, but this increases 

 gradually to 9.4% of SL at 15.9 mm and 11.2% of SL 

 in the juveniles. 



Body Depth 



Body depth ranges from 25 to 30% in newly hatched 

 larvae, but once the yolk is absorbed it decreases to 

 between 21 and 24.4% of SL (with one exception) up 

 to 3.9 mm, and then increases to 22.4 to 33.7% of 

 SL. 



Postanal Length 



Postanal length remains about 45% from 2.0 to 4.9 

 mm SL, when notochord flexion is occurring. A 

 gradual increase to 62.1% in juveniles longer than 

 16.9 mm SL is concurrent with development of ver- 

 tebrae and overall growth of the larvae. 



Preanal Length 



Preanal length increases relative to SL from 36.0 f /f 

 at 2.0 mm to 41.9% at 4.9 mm to >59% for juveniles 

 longer than 16.9 mm. The lengthening of the body 

 cavity during growth accounts for the increase in pre- 

 anal length. 



Head Length 



Head length increases relative to SL from an 

 average of 11.1% (10-12.5%) in newly hatched larvae 

 (2.0-2.3 mm) to 17.3% in 2.6 mm larvae, then 

 gradually increases to 30.2% in the largest juvenile 

 specimen. In very young larvae the otic capsules are 

 the reference structure for head measurements. 

 However, once the cleithrum develops it is used as 

 the reference structure for subsequent head 

 measurements and an increase in head length per- 

 centage is observed. 



Eye Diameter 



The ratio of eye diameter to SL in our series is 6.2- 

 10.9% of SL. It averages 7.5% SL in 2.0-3.0 mm lar- 

 vae, and 8.5% SL (range 8.1-8.9%) in 3.2-4.9 mm 

 larvae. In larvae >4.9 mm the average is 9.5% of SL 

 (range 7.5-10.9%). Variation in individuals of the 

 same size is considerable. 



Prepectoral Length 



Anlagen are present at hatching. Initially prepec- 

 toral length is about 19.2% of SL. This increases 

 gradually during the larval and postlarval period to 

 35.5% of SL in the juvenile. 



Prepelvic Length 



Pelvic fin buds do not appear until the larvae are 

 8.0-8.5 mm long. Prepelvic to SL ratio is about 35.6% 

 (range 33.3-38.4%) for larvae from 8.5 to 15.9 mm 

 SL, but increases to 42.6% of SL in the juvenile. 



MERISTICS 



Scup, being typical of most perciform fish, have 24 

 myomeres. This agrees with Miller and Jorgenson's 

 (1973) vertebrae numbers for adult fish. 



FIN DEVELOPMENT 



At hatching a finfold extends from the top of the 

 head to the visceral sac interrupted only by the anus. 

 There are no fin rays. A remnant of this persists be- 

 tween the anus and the first anal fin ray in a larva 9.1 

 mm long. Fin sequence development is given in Table 

 2. 



Anlagen of the pectoral fins are present in most, if 

 not all, hatchlings. These are low buds at first, but by 

 the time the larvae are about 2.5 mm these fins have 

 bases and blades. By removing pectoral fins from one 

 side of some of our larvae and flattening them out, we 

 could see 13 rays in one 4.9 mm larva and 10 rays in a 

 5.7 mm larva. Aside from these two, however, we 

 could not see pectoral fin rays, even on cleared and 



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