Distribution and some biological features of skate Bathyraja parmifera (Rajidae, Rajiformes) in the northwestern part of the Sea of Japan
In the northwestern part of the Sea of Japan, skate Bathyraja parmifera in catches of the bottom trawl occurs at depths of 40 to 830 m at the near-bottom temperature of 0.4–4.9°C. Throughout the year, the skate performs migrations within the continental slope and, in the feeding period, inhabits mainly the depth range of 300 to 500 m. Maximal average density of aggregations of B. parmifera is observed in waters of northern Primorye; minimal average density is observed in Peter the Great Bay and on the Yamato Bank. In catches, skates with a length of 17–130 cm and a weight of 0.5–18.8 kg are recorded; however, fish with a length of 80–115 cm dominate. Individuals with a length of up to 40 cm feed mainly on amphipods, and larger immature and adult individuals feed on decapods, cephalopods, and fish. The value of the daily ration of B. parmifera with its growth decreases from 2.4 to 0.9% of the body weight. Specific ecological features of B. parmifera are a cause of its considerable underfishing by the bottom trawl; therefore, the total resource of this species in the considered region may be at the level of maximal estimates obtained during surveys and comprise no less than 20000 t.
Two new North Pacific skates (Rajidae) and a revised key toBathyraja in the area
Two new species of the skates,Bathyraja hubbsi andB. pseudoisotrachys are described from the North Pacific. Among the North PacificBathyraja, B. hubbsi most closely resemblesB. violacea Suvorov in possessing a disc without thorns, a median tail thorns irregularly spaced, and minute fine prickles covering the entire dorsal surface. The two species are distinguished from each other by their dorsal color pattern, proportional measurement of tail in relation to total length, clasper components, and number of precaudal vertebrae.Bathyraja pseudoisotrachys has long been confused withB. isotrachys (Günther) by many Japanese authors, but is distinguished from other North PacificBathyraja by dorsal squamation and unique clasper components such as two clefts, terminal bridge and ridge.Bathyraja kincaidii Garman is synonymized with the valid speciesB. interrupta Gill et Townsend.Bathyraja abyssicola Gilbert andB. trachura Gilbert are redescribed in detail. Provisionally, 21 species of the genusBathyraja are recognized in the present study from this region, and a revised key is given to the North Pacific species of the genus.
Miller and Lea's Guide to the Coastal Marine Fishes of California.
This is a comprehensive identification guide encompassing all shallow marine fishes within California waters. Geographic range limits, maximum size, depth range, a brief color description, and some meristic counts including, if available: fin ray counts, lateral line pores, lateral line scales, gill rakers, and vertebrae are given. Body proportions and shapes are used in the keys and a statement concerning the rarity or commonness in California is given for each species. In all, 554 species are described. Three of these have not been recorded or confirmed as occurring in California waters but are included since they are apt to appear. The remainder have been recorded as occurring in an area between the Mexican and Oregon borders and offshore to at least 50 miles. Five of California species as yet have not been named or described, and ichthyologists studying these new forms have given information on identification to enable inclusion here. A dichotomous key to 144 families includes an outline figure of a representative for all but two families. Keys are presented for all larger families, and diagnostic features are pointed out on most of the figures. Illustrations are presented for all but eight species. of the 554 species, 439 are found primarily in depths less than 400 ft., 48 are meso- or bathypelagic species, and 67 are deepwater bottom dwelling forms rarely taken in less than 400 ft. depth. The deepwater forms included are those taken in commercial trawling gear or that occasionally occur near the surface. An illustrated glossary is included to facilitate use of the identification keys and species descriptions. A comments section presents in detail reasons for certain taxonomic choices and to acknowledge personal communications. Original data presented include a ventral sensory pore pattern key for the skates, 170 geographic range limit extensions, and several depth range and maximum size records. Many of the family keys have been revised to incorporate recent taxonomic changes and to clarify previously ambiguous terminology.