Potential use of helminth parasites in stock identification of flying squid, Ommastrephes bartrami, in North Pacific waters

Abstract

A survey of helminth parasites in 68 flying squid (Ommastrephes bartrami) from off the west coast of North America (between latitudes 41°03′ and 48°23′ N and longitudes 129°49′ and 133°08′ W) revealed the presence of numerous juvenile nematodes and cestodes. Larval Hysterothylacium sp. and metacestodes of Phyllobothrium sp. were common (prevalence: 100 and 94.1%, respectively; mean intensity: 54.6 ± 28.1 and 6.4 ± 4.5, respectively). In addition, nine flying squid had a total of 11 Anisakis simplex larvae, and one metacestode of Tentacularia sp. (probably T. coryphaenae) was found in the sample bag that held one flying squid. The only adult helminths recovered were seven specimens of Rhadinorhynchus sp. (Acanthocephala) from three squid. The parasite fauna of these squid was sufficiently different from that previously reported for O. bartrami from the northwestern Pacific Ocean to suggest that parasites may prove useful as a tool to determine if intermixing of squid stocks from their feeding grounds in the eastern and western North Pacific Ocean occurs on the spawning grounds.