366 
Fishery Bulletin 1 13(4) 
Figure 7 
Comparison of the head of Sebastes diaconus (deacon rockfish; ho- 
lotype; OS 18901), on the left side, with that of S. mystinus (blue 
rockfish; OS 18900), on the right side, to show differences in head 
shape and symphyseal protrusion. 
pressed, posterior nostril larger than ante- 
rior and without flap; cranial spines mostly 
absent with the exception of moderately 
weak nasal spines. Mouth terminal and 
moderately sized with posterior margin of 
maxilla extending to vertical through mid- 
pupil, posterior margin of maxilla slightly 
rounded, upper and lower jaw forming 
30-35° angle to central axis of body when 
closed; upper jaw length 36.2-48.1% HL 
(40.9% HL), premaxilla with patches of 
minute conical teeth near symphysis tran- 
sitioning into 2 then 3 rows of teeth along 
posterolateral portion, palatine and vomer 
covered in small conical teeth; lower jaw 
extending anteriorly slightly beyond upper 
jaw, protrusion becoming more distinct with 
growth, lower jaw length 27.4-40.9% HL 
(32.3% HL), mandibular pores minute or ab- 
sent, mandible with 2-3 rows of minute con- 
ical teeth; tongue smooth; symphyseal knob 
pronounced and blunt (Fig. 7A), knob length 
4. 0- 7.0% HL (5.5% HL); gill arch length 
32.3- 46.0% HL (42.3% HL); dorsal margin of opercular 
flap extending posteroventrally at a 25° angle to hori- 
zontal midline of the body, posterior margin of opercu- 
lar flap straight, curving ventrally; opercular spines 2, 
dorsal spine stronger than ventral; preopercular spines 
5, of which dorsal 3 are moderately developed, third 
largest, fourth weak and fifth very weak. 
Predorsal length 28.9-42.4% SL (33.5% SL); prepel- 
vic length 33.3-47.8% SL (39.9% SL); preanal length 
64.0- 77.7% SL (70.3% SL). Dorsal-fin origin above pos- 
terior extent of opercular flap, dorsal-fin base length 
55.0- 68.2% SL (60.9% SL), spinous dorsal-fin base 
32.1- 41.0% SL (36.9% SL), first dorsal-fin spine 2.7- 
6.2% SL (4.7% SL), first spine shortest and subsequent 
spines rapidly increasing in height, longest dorsal-fin 
spine (IV) 9.9-13.4% SL (12.0% SL), spines IV-VII of 
approximately equal length with subsequent spines 
decreasing in size, 1 spine present at origin of rayed 
portion of dorsal fin, rayed dorsal-fin base 20.8-27.6% 
SL (24.0% SL), anterior rays longest and decreasing 
in size posteriorly, fin sloping posteroventrally and 
straight, not curved. Anal-fin margin perpendicular to 
body axis, posterior tips of rays forming nearly verti- 
cal line, anal-fin base 14.6-19.7% SL (17.0% SL), an- 
terior anal-fin rays longest and decreasing in length 
posteriorly, anal-fin spine I length 3.3-6. 7% SL (4.9% 
SL), anal-fin spine II length 7.3—13.6% SL (10.2% SL), 
thicker than others, anal-fin spine III length, usually 
longest, 6.7-14.2% SL (11.0% SL); pectoral-fin length 
23.8- 32.1% SL (28.8% SL), pectoral-fin base height 
7.8- 11.4% SL (10.0% SL), branched rays present on 
dorsal half of fin with transition to unbranched rays 
occurring 1 or 2 rays above the midline of the fin; 
pelvic-fin length 15.8-22.4% SL (19.7% SL), pelvic-fin 
rays decreasing in size from origin, posterior margin 
of pelvic fins slightly rounded; pelvic-fin spine length 
9.3- 14.7% SL (12.3% SL); caudal-peduncle depth 8.9- 
12.7% SL (10.5% SL), dorsal caudal-peduncle length 
8.2-16.3% SL (12.3% SL); ventral caudal-peduncle 
length 14.5-23.1% SL (17.8% SL), caudal fin weakly 
emarginate, length not recorded because of extensive 
damage in many specimens. 
Body covered in rough ctenoid scales; head entirely 
scaled, scales above dorsal opercular opening origin 
unorganized and very small, scales organized into 
loose rows on preopercle and opercle, scales on snout, 
premaxilla, maxilla and lower jaw minute and unor- 
ganized. Trunk scales moderately large, flanked by 
many small accessory scales, especially along posterior 
margins; lateral-line pores conspicuous and forming 
distinct line approximately one-quarter of body depth 
below dorsal margin of body, curving ventrally to reach 
midline of body axis at vertical through dorsal-fin in- 
sertion. Fins completely scaled, with exception of mem- 
branes between dorsal spines and posterior regions of 
unbranched pectoral-fin rays. 
Coloration of live specimens (Figs. 1A and 8A) Body 
overall dark brown to blue-gray, becoming lighter 
posteriorly, ventrum white to light gray; small speck- 
les covering sides of the body but not forming large 
blotches, pattern more evident in mature specimens. 
Juveniles (<100 mm SL) generally darker than adults, 
speckles indistinct or absent on trunk, and difficult to 
distinguish from other dark-bodied species. Head with 
2 dark oblique bars extending posteriorly below orbit, 
1 or 2 additional dark bars over cranium and opercu- 
lar flap. Dorsal-fin membrane dark, lacking spots; cau- 
dal and anal fins uniformly blackish blue, thin light or 
unpigmented band on posterior margin of caudal fin; 
pelvic fins light with blue tips on rays, pelvic-fin spine 
white; pectoral fins dark blue dorsally, with light color- 
ation on unbranched rays and ventral half of pectoral 
fins. Peritoneum dark, usually black to gray, typically 
