The occurrence of branchiobdellidans on stone crayfish (Austropotamobius torrentium) in the Czech Republic

Abstract

The stone crayfish Austropotamobius torrentium (Schrank, 1803) is one of only two native crayfish species in the Czech Republic. Epibiotic branchiobdellidans present on this crayfish species have not been studied before in the Czech Republic. Here we evaluate the occurrence, and basic population characteristics of branchiobdellidans inhabiting A. torrentium in 12 small streams in the Czech Republic. Three Branchiobdella species were found: Branchiobdella parasita, and B. pentadonta dominated. B. hexadonta was found only exceptionally, as we did not focus on species inhabiting the gill chamber. The overall abundance varied between 0.3 and 17 individuals per crayfish. The mean length of B. parasita was 3.58 (1.1-7.1) mm, of B. pentadonta 2.00 (0.9-4.9) mm, and of B. hexadonta 1.73 (1.4-2.2) mm.