Laidig etal.: Description of larval and juvenile Sebastes saxicola 



291 



peared to cease. All other measurements showed a 

 marked increase after flexion was completed (Table 2 ). 



Head spination 



Head spines first began to appear during flexion 

 (Table 3). By 9 mm SL, the postocular, parietal, 

 pterotic, inferior posttemporal, inferior and superior 

 opercular, 1st inferior and 1st superior infraorbital, 

 and all preopercular spines were present. By approxi- 

 mately 10 mm SL, the supracleithral, nuchal, 2nd in- 

 ferior intraorbital, and nasal spines were formed. By 

 20 mm SL, the preocular, superior posttemporal, and 

 tympanic spines formed. The cleithral, 3rd superior 

 infraorbital, and 3rd inferior infraorbital spines were 

 not present in larvae less than 21 mm SL. Supraocular 

 and coronal spines did not occur at any size. 



Pre-extrusion pigmentation 



Pre-extrusion larvae had pigment along the ventral 

 midline extending from the anus to myomere 23 or 

 24 (second and third most posterior myomeres). This 

 pigment was typically strong, with 2-4 melanophores 

 per myomere (Fig. 1A). Pigment consisting of 6-16 

 melanophores was also located along the dorsal mid- 

 line from approximately myomeres 15-23. The dor- 

 sal and posterior surfaces of the gut cavity were also 



heavily pigmented. In addition, in 72% of the larvae 

 very small melanophores (1-5 in number) were ob- 

 served on the ventral surface of the gut cavity. A 

 single melanophore was located in the nape region 

 of the head in 809c of specimens (Fig. 1A). 



Body pigmentation 



After extrusion, melanophores along the dorsal mid- 

 line increased in number and size (Fig. IB). This in- 

 crease was most noticeable in the advancement of 

 pigment in the anterior direction (there was little or 

 no advancement posteriorly). At approximately 12 

 mm SL, the nape and dorsal midline pigments 

 merged to form a solid line along the dorsal body 

 surface. This dorsal body pigment increased in in- 

 tensity as larvae grew. 



A distinct pattern of five body bars (numbered 1-5 

 from anterior to posterior) was apparent in juveniles 

 greater than 25 mm SL. Body-bar 1 began to appear 

 in the nape region at 13 mm SL (Table 4; Fig. ID). 

 This bar extended from the dorsal midline to the 

 operculum and was fully formed by approximately 

 24 mm SL. The next bar to form was body-bar 4 (an 

 inverted triangle under the soft dorsal fin), which ap- 

 peared at 17 mm SL (Fig. IE), and was completely de- 

 veloped by approximately 35 mm SL (Table 4; Fig. IF). 

 Body-bar 2 was the next bar to form ( from the spinous 

 dorsal fin to the dorsal surface of the gut), appearing 

 at approximately 19 mm SL and becoming fully devel- 

 oped by 33 mm SL. Body-bars 3 and 5 ( from the spinous 

 dorsal fin to the anus and an inverted triangle on the 

 caudal peduncle, respectively) were the last bars to 

 form; both appeared at approximately 20 mm SL and 

 were fully developed at 38 mm SL (Fig. IF). 



The postanal ventral midline melanophores near 

 the anus were lost soon after extrusion (Fig IB). By 

 6 mm NL, the anteriormost melanophores were lo- 

 cated approximately three myomeres posterior to the 

 anus. The anterior melanophores decreased in num- 

 ber with increased fish length until approximately 

 10 mm SL. At this size, postanal ventral midline pig- 

 ment began to advance anteriorly with increased fish 

 size. In addition, pigment intensified to form a very 

 dark area extending from the middle of the anal fin 

 posteriorly to the first few ventral pterygiophores of 

 the caudal fin. In larger juveniles (greater than 25 mm 

 SL), the postanal ventral midline pigment became less 

 intense and only a few melanophores remained near 

 the anal fin articulations (Fig. 1, E and F). 



Pigment on the lateral midline began to develop 

 in 6 mm NL fish with a few melanophores near the 

 caudal peduncle (Table 4; Fig. IB). As fish length 

 increased, the lateral midline pigment increased and 

 became most intense at approximately 20 mm SL, 



