Helminth parasites of stellate sturgeon Acipenser stellatus Pallas, 1771 and Persian sturgeon Acipenser persicus Borodin, 1897 (Pisces: Acipenseridae) from the South–East Caspian Sea

A total of 182 specimens of two sturgeon species, stellate sturgeon Acipenser stellatus (N = 112) and Persian sturgeon Acipenser persicus (N = 70), from three coastal stations in the South–East Caspian Sea were examined for endohelminth parasites. Four helminth species were recorded: Cucullanus sphaerocephala (Nematoda: Cucullanidae) and Skrjabinopsolus semiarmatus (Digenea: Acanthocolpidae), found in both host species, and Leptorhynchoides plagicephalus (Acanthocephala: Rhadinorhynchidae) and Amphilina foliacea (Cestodaria: Amphilinidae), found only in A. stellatus. The most abundant parasites were C. sphaerocephala and S. semiarmatus in A. persicus and A. stellatus, respectively. Canonical discriminant analysis was applied for separating host species using parasite numbers data, Brillouin index of diversity, and species richness. By this means, 83% of the hosts were assigned to their correct a priori groups. The different feeding habits and habitat preferences of the two hosts are probably the major factors accounting for the difference in their parasite burdens.