Occurrence of the CopepodEudactylina acanthiiScott, 1901 (Copepoda: Eudactylinidae) as a Gill Parasite on Spiny Dogfish with Comments on a Rare Parasitic Nematode in Eastern Puget Sound, Washington

Abstract

Forty spiny dogfish, Squalus suckleyi, captured in eastern Puget Sound, Washington, were examined for gill parasites, left side only. Nine sharks (22.5%) were found to be without parasites. Frequency of infection for all gill lamellae parasites was relatively equal between males (75%) and females (78.6%). Twenty sharks were infected with the parasitic copepod Eudactylina acanthii, which previously was restricted to S. acanthias and S. mitsukurii. Among the 28 female sharks examined, 60.7% (n = 17) were infected with this copepod compared with 25% (n = 3) of the 12 males. Among sharks infected with worms and copepods, female sharks were twice as likely (77.3%) to be infected with copepods than males (33%). During examination of host sharks, adult philometrid nematodes Phlyctainophora lamnae were found in gill lamellae of one female shark and among larval encasements in caudal peduncle lesions of another female spiny dogfish, and these lesions are documented here with photographs for scientific interest.