ESTABLISHMENT OF THE ZEBRA MUSSEL DREISSENA POLYMORPHA (PALLAS, 1771) IN LOUGH NEAGH, NORTHERN IRELAND

Abstract:Five adult Dreissena polymorpha were found on the hull of a boat moored in Kinnego Marina, Lough Neagh, in November 2005; this is the first indication of their presence in this large lake. This finding initiated a survey to determine whether the zebra mussel was present throughout Lough Neagh. Forty-four settled juveniles on debris were found at twenty sites around the lough shore. As a result of these findings a more extensive study was undertaken in October 2006 to examine planktonic and settled stages. Veliger larvae were at densities of 0.0211 veligers per m⁻³. Spat collectors showed settlement at six out of the seven sites sampled at a mean density of 523.76 juvenile zebra mussels per m⁻². No adult zebra mussels were found on natural substratum in the lough during the shoreline survey. However, 24 adult zebra mussels, 7.5mm to 24mm long, were found on the hull of a boat moored in Lough Neagh.