Bathyraja panthera, a new species of skate (Rajidae: Arhynchobatinae) from the western Aleutian Islands, and resurrection of the subgenus Arctoraja Ishiyama

We provide morphological and molecular evidence to recognize a new species of skate from the North Pacific, Bathyraja panthera. We also resurrect the skate subgenus Arctoraja Ishiyama, confirming its monophyly and the validity of the subgenus. Arctoraja was previously recognized as a distinct subgenus of Breviraja and later synonymized with Bathyraja (family Rajidae). Although the nominal species of Arctoraja have all been considered synonyms of Bathyraja parmifera by various authors, on the basis of morphometric, meristic, chondrological, and molecular data we recognize four species, including the new species. Species of Arctoraja are distributed across the North Pacific Ocean and adjacent seas from southern Japan to British Columbia. Bathyraja parmifera is abundant in the eastern Bering Sea, Aleutian Islands, and northern Gulf of Alaska; B. smirnovi is a western Pacific species found in the Sea of Okhotsk and Sea of Japan; B. simoterus is restricted to waters around the northern and eastern coasts of Hokkaido, Japan; and the new species B. panthera is restricted to the western Aleutian Islands. Bathyraja panthera is diagnosed by its color pattern of light yellow blotches with black spotting on a greenish brown background, high thorn and vertebral counts, chondrological characters of the neurocranium and clasper, and a unique nucleotide sequence within the mitochondrial cytochrome oxidase gene. Furthermore, the species presently recognized as Bathyraja parmifera exhibits two haplotypes among specimens from Alaska, suggesting the possibility of a second, cryptic species.

A habitat-use model to determine essential fish habitat for juvenile brown shrimp (Farfantepenaeus aztecus) in Galveston Bay, Texas

A density prediction model for juvenile brown shrimp (Farfantepenaeus aztecus) was developed by using three bottom types, five salinity zones, and four seasons to quantify patterns of habitat use in Galveston Bay, Texas. Sixteen years of quantitative density data were used. Bottom types were vegetated marsh edge, submerged aquatic vegetation, and shallow nonvegetated bottom. Multiple regression was used to develop density estimates, and the resultant formula was then coupled with a geographical information system (GIS) to provide a spatial mosaic (map) of predicted habitat use. Results indicated that juvenile brown shrimp (<100 mm) selected vegetated habitats in salinities of 15−25 ppt and that seagrasses were selected over marsh edge where they co-occurred. Our results provide a spatially resolved estimate of high-density areas that will help designate essential fish habitat (EFH) in Galveston Bay. In addition, using this modeling technique, we were able to provide an estimate of the overall population of juvenile brown shrimp (<100 mm) in shallow water habitats within the bay of approximately 1.3 billion. Furthermore, the geographic range of the model was assessed by plotting observed (actual) versus expected (model) brown shrimp densities in three other Texas bays. Similar habitat-use patterns were observed in all three bays—each having a coefficient of determination >0.50. These results indicate that this model may have a broader geographic application and is a plausible approach in refining current EFH designations for all Gulf of Mexico estuaries with similar geomorphological and hydrological characteristics.

Description and growth of larval and pelagic juvenile pygmy rockfish (Sebastes wilsoni) (family Sebastidae)

A developmental series of larval and pelagic juvenile pygmy rockfish (Sebastes wilsoni) from central California is illustrated and described. Sebastes wilsoni is a non- commercially, but ecologically, important rockfish, and the ability to differentiate its young stages will aid researchers in population abundance studies. Pigment patterns, meristic characters, morphometric measurements, and head spination were recorded from specimens that ranged from 8.1 to 34.4 mm in standard length. Larvae were identified initially by meristic characters and the absence of ventral and lateral midline pigment. Pelagic juveniles developed a prominent pigment pattern of three body bars that did not extend to the ventral surface. Species identification was confirmed subsequently by using mitochondrial sequence data of four representative specimens of various sizes. As determined from the examination of otoliths, the growth rate of larval and pelagic juvenile pygmy rockfish was 0.28 mm/day, which is relatively slow in comparison to the growth rate of other species of Sebastes. These data will aid researchers in determining species abundance.

Descriptions of larval, prejuvenile, and juvenile finescale menhaden (Brevoortia gunteri) (family Clupeidae), and comparisons to gulf menhaden (B. patronus)

Larval and juvenile development of finescale menhaden (Brevoortia gunteri) is described for the first time by using wild-caught individuals from Nueces Bay, Texas, and is compared with larval and juvenile development of co-occurring gulf menhaden (B. patronus). Meristics, morphometrics, and pigmentation patterns were examined as development proceeded. An illustrated series of finescale menhaden is presented to show changes that occurred during development. For finescale menhaden, transformation to the juvenile stage was completed by 17−19 mm standard length (SL). By contrast, transformation to the juvenile stage for gulf menhaden was not complete until 23−25 mm SL. Characteristics useful for separating larval and juvenile finescale menhaden from gulf menhaden included 1) the presence or absence of pigment at the base of the insertion of the pelvic fins; 2) the standard length at which medial predorsal pigment occurs; 3) differences in the number of dorsal fin ray elements; and, 4) the number of vertebrae.