Species richness, diversity and specificity of the parasites of bream Abramis brama (L.) and perch Perca fluviatilis L. in the estuary of the Odra River, Poland

The parasitological studies were carried out on bream and perch from brackish water of Pomeranian Bay and the Szczecin Lagoon — a mouth of the Odra River. Bream and perch hosted 21 and 13 parasitic species, respectively. The species richness and diversity of parasites were much higher for bream and the abundance of parasites in bream was nearly four-fold higher than that in perch. Faunistic similarity of both parasite communities was low. The dominant group of parasites in both fish hosts was digeneans. Five species were specialists of bream, while only one species was a perch specialist. Five new host records have been reported in Poland for the following species: Myxobolus dispar, Hysterothylacium aduncum, Khawia sinensis, Echinorhynchus gadi and Pomphorhynchus laevis.