A taxonomic revision of Northeast Pacific softnose skates (Rajiformes: Arhynchobatidae: Bathyraja Ishiyama)

Abstract

Softnose skates (Rajiformes: Arhynchobatidae: Bathyraja Ishiyama) are the most diverse skate genus, with 54 species, and are readily distinguishable from other genera in the family by their poorly calcified, flexible rostral cartilages. Six Bathyraja species are considered valid in the eastern North Pacific, including: B. abyssicola, B. aleutica, B. kincaidii, microtrachys, B. spinosissima, and B. trachura. Similar to other skate genera, eastern North Pacific Bathyraja lack a robust species-specific identification, which leads to issues with setting catch limits and creating management plans. This study identifies and formally redescribes the eastern North Pacific softnose skate species based on morphometric and meristic measurements and includes an Alaskan species, Bering Skate, B. interrupta due to its close morphological relationship to B. kincaidii. A lectotype for B. interrupta is designated. Multivariate tests determined that significant differences existed between the study species. Parsimonious phylogenetic trees showed that B kincaidii represents the basal condition, with B. abyssicola and B. aleutica being the most derived species in the study. The formerly synonymized species B. interrupta and B. kincaidii were shown to be separate, as were the previously synonymized species B. microtrachys and B. trachura. Improved Bathyraja species identification will hopefully assist fisheries managers in developing conservation policies easing the impacts of deep-sea fishing expansion.