Sebastes melanops Girard, 1856

Kai, Yoshiaki, Muto, Nozomu, Noda, Tsutomu, Orr, James W. & Nakabo, Tetsuji, 2013, First Record of the Rockfish Sebastes melanops from the Western North Pacific, with Comments on its Synonymy (Osteichthyes: Scorpaenoidei: Sebastidae), Species Diversity 18, pp. 175-182 : 176-181

Sebastes melanops Girard, 1856

[Standard Japanese name: Arasuka-kuro-menuke] [English name: Black Rockfish] ( Figs 2–3 )

Sebastes melanops Girard, 1856: 135 (type locality: Cape Flattery, Washington and Astoria, Oregon, USA); Girard 1859: 81 (Cape Flattery, Washington and Astoria, Oregon, USA); Ueno 1955: 13, fig. 9C (key and list, southern Alaska southward to southern California, USA); Kramer and O’Connell 1995 (key and short description, Aleutian Islands south to Baja California); Orr et al. 2000: 27, fig. 7 (key and short description, Aleutian Islands southward to southern California, USA); Love et al. 2002: 204 (Aleutian Islands off Amchitka Island to southern California off Huntington Beach, USA); Mecklenburg et al. 2002: 361, figure based on Jordan and Evermann (1900) (key and short description, Aleutian Islands off Amchitka Island to southern California off Huntington Beach, USA); Barsukov 2003: 174, fig. 73, pl. 23 (Aleutian Islands to southern California, USA); Orr and Blackburn 2004: 343 (southern Bering Sea).

Sebastes ciliatus (not of Tilesius, 1813): Poltev and Shubin 2013: 191, fig. 2 (east of northern Kuril Islands, Russia).

Sebastodes columbianus Hubbs and Schultz, 1933: 24 , pl. 1, fig. 3 (type locality: Columbia River mouth, on the Washington side between Chinook and Sand Islands, USA) .

Sebastodes melanops : Jordan and Evermann 1898: 1782 (Monterey Bay northward to Kodiak Island, USA); Jordan and Evermann 1900: fig. 655.

Sebastodes melanops melanops: Alverson and Welander 1952: 138 (Washington, USA, British Columbia, Canada, and adjacent areas).

Sebastodes melanops columbianus: Alverson and Welander 1952: 138 (Columbia River mouth).

? Sebastosomus simulans Gill, 1864: 147 (type locality: Cape Flattery , Washington).

Material examined. FAKU 134856, 445.0 mm SL, Miyako, Iwate, Japan, 39.64°N, 141.96°E, 20 April 2012, coll. by T. Noda. Comparative material. Sebastes melanops (24 specimens, 167.4–510.0 mm SL): USNM 342 (syntype of S. melanops , dry specimen, snout broken), Astoria, Oregon, coll. by Lt. Trowbridge; UMMZ 94369 (holotype of S. columbianus ), 427.6 mm SL, Columbia River mouth, on the Washington side between Chinook and Sand Islands, USA; FAKU 122358, 295.8 mm SL, Aleutian Islands, no further detailed collection data; UW 17539, 251.5 mm SL, Humboldt Bay, California, 31 March 1962, coll. by D. Greenfield; UW 41758, 400+ mm SL, Gulf of Alaska, 56.36°N, 154.57°W, 28 June 1996; UW 43057, 235.0 mm SL, Gulf of Alaska, 57.85°N, 152.40°W, 28 July 1977; UW 43252 (3 specimens), 357.0–510.0 mm SL, Gulf of Alaska, 22 July 1996; UW 43421 (2), 386.0 and 423.3 mm SL, Gulf of Alaska, 60.27°N, 145.71°W, 5 September 1993; UW 43422, 410.4 mm SL, Gulf of Alaska, 60.23°N, 146.42°W, 2 April 1994; UW 43425, 410.8 mm SL, Gulf of Alaska, 57.67°N, 155.30°W, 21 March 1994; UW 43489 (3), 167.4–188.8 mm SL, Lisianski Strait, Alaska, 12 July 1998; UW 43490 (2), 177.4 and 213.4 mm SL, Cross Sound, Chichagof Island, Alaska, 11 July 1988; UW 112793–112795 (3), 246.8–307.8 mm SL, 45.48°N, 124.04°W, 29 May 2005; UW 112802, 298.0 mm SL, 45.47°N, 124.01°W, 29 May 2005; UW 113238–113239 (2), 228.1–237.0 mm SL, Whidbey Island, Washington, 48.12°N, 122.43°N, 11 October 2005.

Sebastes ciliatus (11 specimens, 269.1–384.4 mm SL): FAKU 119878 , 119880 , 376.8 and 384.4 mm SL, 59.33°N, 142.36°W; FAKU 121170 , 121171 , 121173–121175 (5), 336.0– 376.4 mm SL, Gulf of Alaska, 55.24°N, 134.13°W; FAKU 131037 , 131038 , 284.6 and 269.1 mm SL, Aleutian Islands, 51.96°N, 176.03°E; FAKU 131039 , 131040 , 297.3 and 348.4 mm SL, Gulf of Alaska, 54.32°N, 161.81°W .

Sebastes mystinus ( Jordan and Gilbert, 1881) (2 specimens, 197.9–202.0 mm SL): USNM 27085 (one of three syntypes of S. mystinus ), 202.0 mm SL, San Francisco , California, USA, coll . by D. S. Jordan; UW 112795, 197.9 mm SL, 45.48°N, 124.04°W .

Sebastes variabilis (7 specimens, 246.1–350.8 mm SL): FAKU S2677 , S2679 , 328.0 and 345.8 mm SL, Aleutian Islands , 53.39°N, 165.28°W; FAKU S3207 , S3210 , 332.4 and 350.8 mm SL, Aleutian Islands , 53.37°N, 165.17°W; HUMZ 53427, 319.1 mm SL, Bering Sea, 56.20°N, 169.20°W; NSMT-P 76226, 350.1 mm SL, Pacific coast of eastern Hokkaido, Japan .

Diagnosis. A species of the genus Sebastes with the following characters: dorsal fin XII–XIII, 14–16 (usually XIII, 15); anal fin III, 8–9 (usually III, 8); pectoral fin 18–19 (usually 19), ventral 9–10 (usually 10) rays unbranched; head completely covered with scales; nasal spine weak; preocular spine usually absent, small and reduced if present; supraocular spine always absent; postocular spine usually absent, small and reduced if present; parietal spine reduced and covered with small scales; symphyseal knob small or absent; distal margin of anal fin slightly rounded below and slanting anteriorly above; caudal fin not distinctly emarginate; body color in life black dorsally, with light blotches below bases of dorsal fins, becoming gray mottled with black on sides, whitish on belly; peritoneum white.

Description. Counts and measurements of S. melanops given in Table 1. Body relatively deep, especially at nape, and compressed. Profile of dorsal margin of head steep from snout to nape. Interorbital region weakly convex. Head and body covered with ctenoid scales with some accessory scales, especially in posterior field. Maxilla, lower jaw, chin, and branchiostegal rays completely covered with small scales. Base of dorsal fin covered with small scales, extending onto spinous and soft-rayed portions. Base of anal fin covered with small scales, extending onto basal membranes.

Nasal spine weak, directed posterodorsally ( Fig. 3 ). Preocular, supraocular, and postocular spines absent. Parietal spine reduced to ridge and covered with small scales ( Fig. 3 ). Anterior and posterior lacrimals both without spine; latter forming weak rounded lobe, its tip below level of anterior margin of pupil. Supracleithral spine simple and flattened, directed posteriorly. Sphenotic, tympanic, and pterotic spines absent. Posttemporal spine embedded, not visible. Preopercle with five diverging spines: upper three large and distinct, directed posteriorly; lower two relatively small and blunt, directed posteroventrally. Opercle with two flattened spines, upper larger than lower, both directed posteriorly. Ventral tip of subopercle and dorsal tip of interopercle each with small spine.

Mouth large, slightly oblique; posterior margin of maxilla extending to posterior rim of orbit. Lower jaw projecting anteriorly; symphyseal knob absent. Mandibular pores small and indistinct except for anteriormost one. Villiform teeth on both jaws, vomer, and palatines; those on vomer forming V-shaped patch. Gill rakers long and slender, longest somewhat shorter than longest gill-filament. Dorsal-fin spines 13, gradually increasing in length to fifth spine, thereafter decreasing in length to 12th spine, 13th spine longer than 12th spine, forming anterior support of soft dorsal fin. Second anal-fin spine shorter than third; second anal-fin ray longest, posterior rays gradually shortening. Distal margin of anal fin slightly rounded below and slanting anteriorly above. Caudal fin not distinctly emarginate, lobes not pointed. Pectoral fin not pointed; its tip not reaching level of anus; ventral 10 rays neither branched nor thickened. Posterior tip of depressed pelvic fin extending to level of pectoralfin tip, not reaching to anus.

Coloration in life. Body black dorsally, with light blotches below base of dorsal fins, becoming gray mottled with black on sides, whitish on belly. Head black; mandible whitish. Dorsal fin dark bluish-brown with indistinct dark spots on basal part. Anal fin dark bluish-brown, distal margin somewhat paler. Caudal and pectoral fins black. Pelvic fin light bluish-brown, basal part somewhat whitish. Peritoneum white.

Coloration in preservative. Body dark on back, becoming pale with indistinct dark dots on side, light on belly. Head dark; mandible pale. Dorsal, anal, caudal, and pectoral fins dark. Pelvic fin whitish. Peritoneum light.

Distribution. Currently known from the eastern North Pacific, i.e., from the Aleutian Islands off Amchitka Island and the southeastern Bering Sea to Baja California off Huntington Beach, and from the western North Pacific east of the northern Kuril Islands and off Miyako, Iwate, Japan ( Kramer and O’Connell 1995; Love et al. 2002; Mecklenburg et al. 2002; Poltev and Shubin 2013; this study) ( Fig. 1 ).

Remarks. The counts and measurements of the specimen collected from Japan are consistent with those from the eastern North Pacific ( Table 1). In addition, the head spine structure, absence of a symphyseal knob, rounded anal fin, and light peritoneum of the Japanese specimen completely agree with the specimens from the eastern North Pacific. In the comparison of mtCR sequence variation (371 aligned base pairs including 5 indels), the Japanese specimen clustered with the eastern North Pacific specimens of S. melanops with high bootstrap probability, and were distinct from S. flavidus and S. serranoides , which were the most closely related species within Sebastes , as well as the more distantly related S. ciliatus and S. variabilis ( Hyde and Vetter 2007) ( Fig. 4 ). Although S. variabilis was paraphyletic with respect to S. ciliatus , such relationships between closely related species are well known in Sebastes (reviewed by Muto et al. 2011). The uncorrected distance between the Japanese and the eastern Pacific specimens of S. melanops was 0.27– 1.35%, which falls within the typical range of intraspecific variation of Sebastes ( Kai et al. 2002, 2011; Hyde and Vetter 2007; Muto et al. 2011). Sebastes melanops was previously known from the Aleutian Islands and the southeastern Bering Sea to Baja California, USA, and the present specimen represents the first confirmed record of this species from the western North Pacific ( Mecklenburg et al. 2002; Parin et al. 2002; Barsukov 2003; Nakabo and Kai 2013). An additional specimen (ca. 400 mm SL) of S. melanops was also captured by a set-net in Miyako, Iwate, Japan ( Fig. 2B ), but was not available for examination in this study. The presently described specimen was a spent male with small testes, but it is unclear whether this species reproduces in Japanese waters.

Sebastes melanops was first described by Girard (1856) based on several specimens collected from two localities, Cape Flattery, Washington, and Astoria, Oregon, USA, without designation of a holotype. Therefore, all the specimens used by Girard (1856) are syntypes (Art. 73.2., ICZN 1999) and the type locality of S. melanops includes both Cape Flattery and Astoria. Although no catalog numbers of type specimens were given in the original description, USNM 342 (two specimens, collected from Astoria, Oregon, USA) has been regarded as containing the syntypes of S. melanops (J. T. Williams, USNM, personal communication; Eschmeyer 2013). Later, Girard (1859) redescribed S. melanops on the basis of four specimens: USNM 341 (two specimens, collected from Cape Flattery, Washington, USA) and USNM 342. Because the collection localities of USNM 341 and 342 are the same as the type localities of S. melanops , it is most plausible that both USNM 341 and 342 are the syntypes of S. melanops . According to Girard (1859), both USNM 341 and 342 included two specimens, but only a single specimen of USNM 342 is now extant in the USNM, and was thus available for this study. The counts of anal- and pectoral-fin rays, and the head spine structure of the present specimens identified as S. melanops , including the specimens collected from Japan, agree well with USNM 342. In addition, the original description of Girard (1856) noted that the type specimens had a blackish brown body mottled with black, consistent with the S. melanops examined here. However, USNM 342 has 12 dorsal-fin spines, a count different from the present specimens. Species of Sebastes usually have 13 dorsal-fin spines ( Matsubara 1943), but many species show a range of variability from 12 to 14 spines (e.g., Orr and Blackburn 2004; Kai and Nakabo 2008, 2013). Therefore, we regard the count of 12 dorsal-fin spines of USNM 342 as intraspecific variation within S. melanops .

After Girard (1856), Gill (1864) stated that “two species are apparently confused by Girard under the name Sebastes melanops .” According to Gill (1864), the specimens collected from Astoria and those from Cape Flattery were different species. He claimed the former should be identified as S. melanops , and the latter he named as a new species. Sebastosomus simulans described on the basis of USNM 3309. This may indicate that USNM 3309 from Cape Flattery is also one of the type series of Sebastes melanops , but no such records were found in the database of the USNM (J. T. Williams, personal communication). Although many authors, including Jordan and Evermann (1898), Love et al. (2002), and Barsukov (2003), have treated S. simulans as a synonym of S. melanops without any clear reason, USNM 3309 is inconsistent with the present specimens of S. melanops in that it has 18 pectoral-fin rays and a short upper jaw not reaching below the posterior rim of the pupil. We confirmed these characters in USNM 3309 from a photo and a radiograph; thus S. simulans may not be conspecific with S. melanops . Further study will be needed, including a detailed examination of the holotype, to conclusively determine the status of S. simulans .

Hubbs and Schultz (1933) described Sebastodes columbianus as a new species on the basis of five specimens collected from the mouth of the Columbia River , Washington, USA . They diagnosed it by its small eye, 14 dorsal-fin rays, and nine unbranched pectoral-fin rays. The holotype of S. columbianus ( UMMZ 94369 ) has a relatively smaller eye and shorter pectoral and pelvic fins than the specimens presently identified as S. melanops , but these differences seem insignificant and attributable to its large body size ( Table 1). In addition, the counts of unbranched pectoral-fin rays and dorsal-fin rays were within the range of the present specimens identified as S. melanops ( Table 1). Therefore, we regard S. columbianus as a junior synonym of S. melanops . Alverson and Welander (1952) recognized two subspecies, S. melanops melanops and S. melanops columbianus , under S. melanops , mainly based on a difference in the number of unbranched pectoral-fin rays. They considered S. melanops columbianus to be distributed only in the Columbia River mouth, but in tagging experiments, Mathews and Barker (1983) recovered a few individuals of S. melanops from the San Juan Islands in areas between Westport, Washington, and the Columbia River mouth, and also mentioned that a tagged S. melanops moved 619 km from the central Oregon coast northward into Puget Sound. In addition, USNM 342 , one of the syntypes of S . melanops, was collected from Astoria, Oregon in the Columbia River mouth, which is very close to the type locality of S . columbianus. In the absence of morphological evidence, the recognition of S. melanops columbianus as a valid subspecies is thus not appropriate.

Poltev and Shubin (2013) reported “ S. ciliatus ” from the northern Kuril Islands, but the photo given by them agrees instead with the present specimens regarded as S. melanops in body coloration and the absence of a symphyseal knob. Although they reported 11 specimens, their report lacked a detailed morphological description based on voucher specimens. Nonetheless, we tentatively identify the two specimens shown in their photo as S. melanops , noting that the site is midway between Amchitka Island and the present site off northern Honshu ( Fig. 1 ).

Ueno (1955) proposed new Japanese names for the species of Sebastes known from the Bering Sea and Gulf of Alaska provided brief descriptions of them, and also made comparisons with the species known from Japanese waters. Although S. melanops had not been recorded previously from these waters, Ueno (1955) gave it the Japanese name “Arasuka-kuro-menuke.” We adapt this name here.

Comparison. Sebastes melanops most closely resembles S. ciliatus , S. variabilis , S. flavidus , and S. serranoides in having a weak head spine structure and dark coloration on the back, but it can be distinguished from them by the symphyseal knob, color of the peritoneum, shape of the anal fin, and the counts of the pectoral-fin rays ( Orr et al. 2000; Orr and Blackburn 2004; this study). The symphyseal knob is absent or reduced in S. melanops , consisting only of a fleshy pad at the tip of the mandible, unlike the distinct bony knob of S. ciliatus and S. variabilis . In S. melanops , the peritoneum is usually light (white in life), but it is typically jet black in S. ciliatus and dark gray in S. variabilis . The distal margin of the anal fin of S. ciliatus , S. flavidus , S. melanops , and S. serranoides is rounded, but that of S. variabilis is typically pointed. There are typically 19 pectoral-fin rays in S. melanops , but typically 18 in S. ciliatus , S. flavidus , and S. variabilis , and typically 17 in S. serranoides .

Sebastes mystinus is also similar to S. melanops but may be distinguished by the four distinct dark bars across its head and nape. The mouth of S. mystinus is smaller than that of S. melanops , and the maxilla extends only to the middle of the pupil rather than reaching the posterior margin of the orbit as in S. melanops .

Figures

Fig. 2. Color photographs of fresh specimens of Sebastes melanops. A: FAKU 134856, 455.0mm SL, Miyako, Iwate, Japan; B: uncollected specimen, Miyako, Iwate, Japan.

Fig. 3. Lateral view of head of Sebastes melanops, FAKU 134856, 455.0mm SL.

Fig. 1. Distribution of Sebastes melanops based on literature records (shaded area) and collection sites of specimens examined (symbols). Open star: syntypes of S. melanops; solid star: syntypes of S.melanops and S.columbianus; open circles: other material.

Fig. 4. Unrooted neighbor-joining tree based on sequence variations of the mitochondrial control region. Sequences used here are referred to by catalog numbers of the specimens (determined here) or DDBJ registration numbers (indicated by asterisks, determined in previous studies). Numbers at branches indicate bootstrap probabilities in 1,000 bootstrap replications. The scale bar equals 0.01 of Kimura’s (1980) distance.