Orr and Blackburn: Resurrection of Sebastes variabilis and redescription of Sebastes ciliatus 



343 



bills were dissected in the present study to examine these 

 muscles. Additional material should be examined to assess 

 the intraspecific variability and systematic significance of 

 this character complex. 



Typical habitats of these two species also differ. Adult 

 S. ciliatus are found in nearshore shallow habitats at 

 maximum depths of 160 m and are abundant in protected 

 coves on the outer coast of Alaska. Sebastes variabilis, in 

 contrast, is found along the continental shelf margin at 

 depths to 675 m. However, adult S. variabilis have also 

 been collected in nearshore waters as shallow as 40 m ( UW 

 43494). In areas of sympatry, such as the inside waters 

 in Lynn Canal of southeast Alaska and Monashka Bay of 

 Kodiak Island, S. variabilis is found at greater depths in 

 stronger current, whereas S. ciliatus is found, often with 

 S. melanops, among kelp (Macrocystis) on rocky ledges 

 (Blackburn and Orr, personal observ. ). 



Other uniformly dark colored species of Sebastes, such 

 as S. melanops and S. mystinus, may also be confused 

 with S. ciliatus and darker individuals of S. variabilis, al- 

 though both may be distinguished on the basis of color and 

 morphological features. The body of S. melanops is dark 

 bluish-black, has black speckling on the dorsum and lat- 

 eral surfaces, and a distinctly white ventrum (in contrast 

 with the slightly lighter ventrum of S. ciliatus (Fig. IE]). 

 Unlike S. ciliatus, in which the peritoneum is jet black, S. 

 melanops has a white peritoneum. In S. melanops, five or 

 six faint light blotches slightly larger than the orbit are 

 present on the dorsum about midway between the lateral 

 line and the dorsal-fin base. These blotches are especially 

 prominent underwater, and in Alaska easily distinguish 

 S. melanops from both S. variabilis and S. ciliatus, which 

 lack blotches (Lauth 8 ; see color figures of Love, 2002, and 

 Stewart and Love, 2002). The symphyseal knob in S. 

 melanops is obsolete, consisting only of a fleshy pad at the 

 tip of the mandible, unlike the distinct bony knob of S. 

 ciliatus and S. variabilis. Mandibular pores of S. melanops 

 are obsolete, as compared with the larger, readily appar- 

 ent pores of S. ciliatus and S. variabilis. Vertebral counts 

 also differ, from 28-29 in S. ciliatus and S. variabilis to 26 

 in S. melanops. Sebastes melanops ranges from southern 

 California to Atka Island in the Aleutian Islands (Meck- 

 lenburg et al., 2002) and the southern Bering Sea, where 

 its presence is documented by a single recent collection 

 (UW 47037). Most previous reports from the Bering Sea 

 may be of S. ciliatus. 



Sebastes mystinus is also similar to S. ciliatus but may 

 be distinguished by the four distinct dark bars across its 

 head and nape contrasting with its general body color of 

 light mottled bluish-gray. The mouth of S. mystinus is 

 smaller than that of S. ciliatus, and the maxilla extends 

 only to the middle of the pupil rather than to the posterior 

 portion of the orbit as in S. ciliatus. Like S. melanops and 

 most Pacific Sebastes, S. mystinus has 26-27 vertebrae, 

 compared to the 28-29 vertebrae of S. ciliatus and S. 



s Lauth, R. R. 1998. Personal commun. Resource Assess- 

 ment and Conservation Engineering Division, Alaska Fisheries 

 Science Center, Natl. Mar. Fish. Serv., NOAA, 7600 Sand Point 

 Way NE, Seattle, WA 98115. 



variabilis. Sebastes mystinus has been recorded from Sitka 

 Harbor, Alaska (Kramer and O'Connell, 1995), to Punta 

 Santo Tomas, northern Baja California (Hobson, 2002). 

 Earlier reports from Kodiak Island, the Aleutian Islands, 

 and Bering Sea are undocumented ( Quast and Hall. 1972 ; 

 Kramer and O'Connell, 1995; Mecklenburg et al., 2002) 

 and probably refer to S. ciliatus. 



Sebastes polyspmis is commonly caught in trawls and 

 may be confused with S. variabilis, especially when pre- 

 served. It can be distinguished from S. variabilis by its 

 modal count of 14 dorsal-fin spines and light (pink or white 

 when live) oblique band across the lower rays of the pecto- 

 ral fin, which remains prominent when recently preserved. 

 In life, the overall color of S. polyspinis is reddish-orange 

 to pink, overlaid with gray-green mottling and fine green 

 spots. Evermann and Goldsborough (1907) considered the 

 then undescribed S. polyspinis within the range of varia- 

 tion of "S. ciliatus" because at least one lot (USNM 6243) 

 was misidentified by them as "S. ciliatus." They probably 

 also confused S. melanops with S. variabilis, or possibly S. 

 polyspinis, describing the color in life of S. melanops from 

 Alaska as "olive-brown, blotched with dirty red." Sebastes 

 melanops never has a trace of red, whereas the most com- 

 mon color pattern of S. variabilis could be adequately 

 described by this phrase. 



In the western Pacific, two species, the dark-colored S. 

 taczanowskii and the light-colored S. schlegelll, may be 

 confused with S. ciliatus and S. variabilis, respectively. 

 Both may be distinguished from S. ciliatus and S. varia- 

 bilis by modal counts of pectoral-fin rays (15 in S. tacza- 

 nowskii and 17 in S. schlegelii vs. 18 in both S. ciliatus and 

 S. variabilis) and vertebrae (26 in both S. taczanowskii 

 and S. schlegelii vs. 28-29 in S. ciliatus and S. variabilis). 

 Sebastes schlegelii may also be distinguished by its typi- 

 cal dorsal-fin spine count of 12 (vs. 13 in S. ciliatus and S. 

 variabilis). 



Implications for fisheries management 



The dusky rockfish (S. variabilis) and the dark rockfish 

 (S. ciliatus) have been subjected to two distinct fisheries 

 separately managed by U.S. federal and Alaska state 

 agencies: S. variabilis is captured in the offshore trawl 

 fishery; S. ciliatus, in the nearshore jig fishery. Although 

 the offshore fisheries for dusky rockfish only inciden- 

 tally catch the dark rockfish and are managed for dusky 

 rockfish, the nearshore fishery is not managed for dark 

 rockfish, and instead the species has been routinely mis- 

 identified as black rockfish (S. melanops). Sebastes ciliatus 

 has been found to comprise up to 25 < 7<r of the catch in the 

 "black rockfish" jig fishery of the northern Gulf of Alaska 

 (Clausen et al. 1 ). 



Several differences in biologically significant param- 

 eters were evident from specimens examined in our study 

 and from observations in survey data. The two species 

 are typically found in different habitats, attain different 

 maximum sizes, and show differences in reproductive 

 seasonality. Recognizing the two as distinct species is the 

 first step towards establishing a biologically based, spe- 

 cies-specific management scheme. 



