Early larvae of the swordspine rockfish (Sebastes ensifer) identified by molecular methods


Watson, William, Sharon R. Charter, and Cynthia A. Taylor Lawley
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About 56 rockfish (Sebastes) species occur in Southern California, but the larvae of most of them are undescribed. Larval rockfishes collected off Southern California during the California Cooperative Oceanic Fisheries Investigations (CalCOFI) cruise in April 1999 and the Baseline Cowcod Conservation Area (CCA) cruise in February 2002 were identified by using mitochondrial cytochrome b genomic DNA to determine the abundances of individual species. About 27% of the larvae from the CalCOFI cruise and 16% of the larvae from the CCA cruise were Sebastes ensifer. Larval S. ensifer were undescribed for most of the size range identified here (2.6–8.4 mm, early preflexion through early postflexion stage). Larval S. ensifer are moderately deep-bodied and robust and have melanophores dorsally and ventrally on the gut, in a single ventral row on the tail, and on the pectoral fins. Starting at about 3.8 mm, melanophores form on the anterior part of the mandible. Larvae ≥6 mm have pigment in the mid- and hindbrain areas. Preflexion-stage larval S. ensifer are indistinguishable from the described larvae of sympatric species in the Sebastes subgenus Sebastomus, except perhaps Sebastes rosaceus and S. umbrosus. In later stages, S. ensifer may be distinguishable from S. constellatus and S. helvomaculatus.