Expansion of Phalacrocorax carbo in reservoirs of the North-Eastern Kazakhstan

Abstract

Initial data regarding the helminth fauna of the great cormorant (Phalacrocorax carbo) in the Pavlodar region of Kazakhstan have been acquired. The parasite fauna of the great cormorant is influenced by its diet of fish and consists of two fully developed helminth species - the nematode Contracaecum rudolphii Hartwich, 1964 and the cestode Ligula interrupta Rudolphi, 1810. An incidental finding was made when cestodes and their broken pieces were found in the intestines of cormorants. These cestodes were recognised as belonging to the genus Cyathocephalus, which is known to solely parasitize fish in its adult stage. Metacercariae of trematodes, specifically from the family Strigeidae, were found. These parasites are very new to fish intestines and are not commonly found in birds that consume fish. The growing population of great cormorants in the Ertis basin may introduce new kinds of helminths, some of which could have significant implications for the spread of diseases among animals. The prevalence of parasites in cormorants is a significant concern and has the potential to facilitate the transmission of nematodes and cestodes among other species, including fish-eating birds, poultry, fish, and aquatic invertebrates. This creates localised areas where nematodes and ligulidoses can thrive.