A New Species of Sebastes from the Northeastern Pacific, and Potential Implications for Rockfish Management

Though 106 species of rockfishes in genus Sebastes are considered valid, many of the ecological, geographical, and morphological boundaries separating those species lack clarity.  Herein, we clarify one such boundary by separating the Blue Rockfish Sebastes mystinus (Jordan and Gilbert, 1881), into two species using molecular and morphological data. Aside from unambiguous distinction at six microsatellite loci, the new species is most easily differentiated from S. mystinus by possessing a solid rather than a blotched trunk body color pattern. It also possesses a prominent symphyseal knob versus a reduced or absent knob, a flat rather than rounded ventrum, and longer first and second anal-fin spines. Based on museum material and previous molecular work, the new species occurs from the coastal waters of central California northward to British Columbia while S. mystinus occurs from northern Oregon south to Baja California Sur, implying broad sympatry in Oregon and Northern California. Further collection and study are necessary to clarify distributional boundaries of these species and understand their ecology and mechanisms of segregation. Additionally, fisheries assessments of Blue Rockfish stocks and the minor near-shore rockfish complex will need revision to account for the longstanding conflation of the two species.