Helminth fauna of spawning pacific herring <i>Clupea pallasii</i> from the Taui population (Tauiskaya Guba Bay, Okhotsk Sea)

Abstract

Parasites of spawning pacific herring (Clupea pallasii Valenciennes in Cuvier et Valenciennes, 1947) from the Taui population are explored on the samples caught on two spawning grounds located in the Ola lagoon and Amakhton Bay (Tauiskaya Guba Bay, Okhotsk Sea), and 17 species of helminthes are found, including 6 trematodes, 5 cestodes, 4 nematodes, and 2 acanthocephalans. Some differences in species composition of helminthes and their infestation were found between these estuarine and marine spawning grounds. In the Ola lagoon, 16 species of helminthes were identified, including 5 species of cestodes, whereas only 13 species of helminthes, including 3 species of cestodes, were found in the Amakhton Bay. The Taui population of herring is distinguished from the Okhotsk and Gizhiga-Kamchatka populations by presence of nematodes Hysterothylacium aduncum, l, and Ascorophis pacificus with rather high rates of invasion (occurence = 52.9 %; mean abundance = 4.16) and trematode Bucephaloides spp. On the other hand, the herring from the Taui population has common dangerous parasites with other populations in the Okhotsk Sea, as trematode Brachyphallus crenatus and nematode Anisakis spp. (larvae), with high degree of infestation.