First Record of Jaera Istri Veuille, 1979 (isopoda, Janiridae) in Poland: Eastward Invasion from the Mittelland Canal

During a survey of zoobenthos along the middle and lower Oder River in October 2011, the Ponto-Caspian isopod, Jaera istri Veuille, 1979, was collected for the first time in Poland, ca. 160 km east from its earlier known localities in the river Elbe. The species was found in several locations in the lower part of the river: mostly downstream from the mouth of the artificial canal joining the river Havel in Germany to the Oder. As the species was not recorded in the Oder during extensive sampling in 2009 and in 2010, we can assume that it arrived in the Oder recently through the Havel-Oder Canal. No individuals of the species were found in the Oder more than 30 km upstream of the canal mouth so far.