Records for fifteen species of stoneflies (Amphinemura sulcicollis, Nemoura avicularis, Nemoura cinerea, Nemurella pictetii, Protonemura meyeri, Leuctra fusca, Leuctra hippopus, Leuctra inermis, Capnia atra, Capnia bifrons, Diura bicaudata, Isoperla grammatica, Perla bipunctata, Chloroperla tripunctata and Siphonoperla torrentium) from the Corrib catchment basin in the west of Ireland are presented. Their distributional patterns are considered in relation to habitat characteristics, including water chemistry, and the general topographical and geological features of the area. Predation by fish on stoneflies in alkaline streams was also investigated.