THE PARASITE FAUNA OF COREGONIDS FROM LOWER OB TRIBUTARIES AND THE KHATANGA RIVER

Abstract

A comparative analysis was carried out investigating the parasite faunas of coregonids (humpback whitefish, peled, least cisco, and tugun) from the Lower Ob Ural tributaries (Rivers Synya, Voykar, Severnaya Sos'va, Sob, Shchuch'ya) and from the Khatanga River. Surveys revealed 48 parasite species, most with a complex life cycle (29 helminth species and 3 myxosporidian species whose development involves benthic organisms). Semi-anadromous whitefish spawning in Lower Ob tributaries were shown to have a poorer species composition of parasites (13-16 species) compared to land-locked whitefish from the Khatanga (23 species). The parasite fauna of semi-anadromous peled from the Lower Ob had the most diverse species composition among the rest of coregonids, with relatively high similarity between the rivers Voykar and Synya, while that of the S. Sos'va River stood apart. Resident ecotypes of peled from the rivers Shchuch'ya and Khatanga were similar in the species composition of their parasites in spite of the substantially different geographical locations of the catchments. Least cisco within the Lower Ob basin (Rivers Voykar and Sob) featured a high similarity of the parasite species composition, which was, however, very different from that in least cisco from the Khatanga. Some freshwater parasites (infusorians, monogeneans, trematodes and leeches) apparently get lost in the brackish waters of Khatangsky Bay, while the crustacean Coregonicola orientalis is introduced into the river during the spawning run. The parasite fauna of tugun was the richest in the Khatanga (17 species), relatively poor in the Sob (5) and Shchuch'ya (6 species), and generally reflected the features of the fish ecology in each specific river.

Keywords

• peled
• least cisco
• tugun
• humpback whitefish
• parasites
• lower ob tributaries
• khatanga river