Morphology, biology and parasite fauna of the least cisco (Coregonus sardinella) of the Yenisei River
Morphology, biology and parasite fauna of the least cisco (Coregonus sardinella) of the Yenisei River

Summary/Abstract: In the present study, we present an analysis of the morphological and ecological characteristics of the “turukhanskaja” form of the Siberian least cisco of the Yenisei River, including the characters of the size-age, sexual composition of the population, fecundity and growth. The variability of 34 morphological characters was studied. Significant differences were noted between males and females of the least cisco of the Yenisei River for 11 morphometric characters (head length, maximum body depth, caudal peduncle length, antepectoral distance, dorsal fin base length and dorsal fin depth, anal fin base length, pectoral fin length, head width, head (at nape), interorbital width). Significant differences in meristic characters were revealed in comparison of the least cisco from the Yenisei River with populations of Siberian least cisco from other water bodies. It was shown that the Yenisei least cisco is close to the European vendace Coregonus albula Linnaeus, 1758 not only according to cluster hierarchical analysis for some meristic and morphometric features but also in terms of growth and fecundity. In general, the Yenisei least cisco, as well as other populations of least cisco of the Taimyr, is characterized by heterogeneity in the structure of populations. The parasite fauna of Yenisei’s Siberian cisco, captured in the area of Dudinka town, consists of 17 species of parasites from seven systematic groups. It is dominated by Diphyllobothrium ditremum (Creplin, 1825) and Discocotyle sagittata (Leuckart, 1842). The feature of the parasite fauna of least cisco from Yenisei River in comparison with the Ob River (neighbouring water basin) is a low infection with trematodes and a high species diversity of Acanthocephala. The reason for the low infection with trematodes may be differences in the hydrological conditions of the water bodies, which in the Yenisei are unfavourable for the development of intermediate hosts of trematodes. Siberian cisco from the Yenisei River is a carrier of Diphyllobothrium dendriticum (Nitzsh, 1824), a species that can cause human disease.

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