Porcupine Newsletter Number 25, Winter 2008/09.

Diversity of intertidal non-nativespecies in WalesKathryn BirchCountryside Council for Wales, Maes yFfynnon, Ffordd Penrhos, Bangor, LL57 2DWThis talk will look at the non-native species foundon the Welsh intertidal. Most of the informationwas gathered during the Welsh intertidal surveycarried out by CCW between 1996 & 2006 withsome additional information to bring the story upto date.Fourteen non-native species have been recordedon the Welsh intertidal spread across the differenttaxonomic groups: 5 algae, 4 molluscs, 1 polychaete,1 anemone, 1 ascidian, 1 barnacle and 1 crab asshown in table 1.Four of the more invasive species will be looked at inmore detail: Japanese wireweed Sargassum muticum,non-native oysters Crassostrea gigas and Tiostrealutaria cultivation and the recent introduction in2006 of America slipper limpet Crepidula fornicatainto the Menai Strait with mussel seed and subsequentaction taken to deal with the problem.A full write-up of the intertidal survey includinga section on non-native species can be found in‘Wyn, G., Brazier, P., Jones, M., Lough, N., Birch,K., Bunker, A. and Brunstrom, A. 2007. When thetide goes out: the biodiversity and conservationof the shores of Wales, CCW’.Table 1 Non-native species recorded on the Welsh intertidal.Species nameElminius modestusTypeBarnacleNo. sites197Codium fragile subsp. tomentosoides Green alga 30*Mya arenaria Mollusc 28Crepidula fornicata Mollusc 26Colpomenia peregrina Brown alga 24Sargassum muticum Brown alga 10Styela clava Ascidian 9Crassostrea gigas Mollusc 7Antithamnionella spirographidis Red alga 2Ficopomatus enigmaticus Polychaete 2Haliplanella lineata Anemone 1Solieria chordalis Red alga 1Tiostrea lutaria Mollusc 1Eriocheir sinensis Crab Not recorded in intertidal survey* Included records of the green algae Codium fragile and Codium fragile subsp. tomentosoides because not allspecimens were collected for subspecies identification.30PMNHS Newsletter No.25 Winter 2008/09