Consumption of the invasive New Zealand mud snail (Potamopyrgus antipodarum) by benthivorous predators in temperate lakes: a case study from Lithuania

Abstract

Introduced species interact both directly and indirectly with native species. Of particular interest from the fisheries management point of view is how the invasive New Zealand mud snail, Potamopyrgus antipodarum, can alter the diet of fish and crayfish. If the snail is somewhat resistant to predation, it cannot be easily included into predators’ diet. We examine the direct interactions between the introduced P. antipodarum and benthivorous predators local to temperate lakes through laboratory experiments and field surveys. Field survey showed that P. antipodarum dominated in the macroinvertebrate communities of the studied lakes. Feeding experiments indicated low consumption of P. antipodarum by most of its potential predators. Field diet survey showed that the main fish species did not significantly consume P. antipodarum. Moreover, it was ascertained that this snail can survive passing through the gastrointestinal tract of most studied fish species. Consequently, as local fish do not consume P. antipodarum, a part of lake primary production becomes locked in lower trophic levels. Therefore, there is a legitimate concern that the invasion of this snail may reduce the direct flow of primary production towards higher trophic levels in temperate lakes.