Transmission pathways of the helminths of the digestive system of the european perch Perca fluviatilis (Actinopterygii: Perciformes) in the fish communities of the water bodies of the national park “Samarkskaya Luka” (Russia)

Abstract

Studied the dynamics of infection of the European perch Perca fluviatilis (Peciformes) by the helminths of the digestive system and their invasion of 13 native and 2 alien fish species in the water bodies of the National Park “Samarskaya Luka”. The similarity of the composition of the fauna of helminths of the digestive system of the European perch and other fish species has been analyzed for the period of 1990-2016. Peculiarities of the distribution of Perca fluviatilis parasites along the trophic chains of the fish community at different stages of ecosystem succession were revealed. Human activity promoted the penetration of alien species of aquatic organisms into the water bodies, their incorporation into the trophic chains and parasitic sub-systems “fish – helminths of the digestive system”. The historically established trophic relations of carnivorous fish with Perca fluviatilis are nowadays weakened; usual food objects are replaced by the invasive fish species. Invasive species participae actively in the formation of trophic chains of the ecosystem; in some cases, it leads to an increase in the invasion rates of indigenous hosts by alien parasites.