The mottled skate Beringraja pulchra is a coastal fish caught by gillnet and bottom trawl fisheries in Hokkaido, Japan. We recently found a parasitic copepod identical to Pseudocharopinus markewitschi (Gusev, 1951) on this commercially important fish. A total of 109 host individuals caught off the coast of northern Hokkaido, Japan, were examined for adult females of this copepod, and 67 cases (61.5%) of infection comprised with 31 cases (67.4%) of 46 males and 36 cases (57.1%) of 63 females were found. The parasite specimens (n = 229) were recovered mainly from the dorsal side of the pelvic fin (n = 168, 73.4%), followed by the claspers (n = 32, 14.0%). The mottled skate is thought to spend most of its lifetime lying in sand or crawling on the seafloor. Therefore, the biased infection to the dorsal side of the pelvic fin may imply that site selection favors less susceptible for disturbances resulting from such host-specific behavior.

斑驳鳐Beringraja pulchra是日本北海道刺网和底拖网渔业捕获的一种沿海鱼类。我们最近在这条具有重要商业价值的鱼身上发现了一种与Pseudocharopinus markewitschi (Gusev, 1951)相同的寄生桡足类动物。对日本北海道北部海岸捕获的 109 名寄主个体进行了成年雌性桡足类动物的检查，其中 67 例（61.5%）感染，其中 31 例（67.4%）46 例男性和 36 例（57.1 %) 中发现了 63 名女性。寄生虫标本（n  = 229）主要来自腹鳍背侧（n  = 168, 73.4%），其次是钩环（n = 32, 14.0%)。人们认为，斑驳的鳐鱼一生中大部分时间都躺在沙子里或在海底爬行。因此，对腹鳍背侧的偏向感染可能意味着位点选择有利于不太容易受到这种宿主特异性行为引起的干扰的影响。