Download

Aquatic invertebrates were extracted and identified from seven Blue Duck faeces collected from the Tongariro River in December 1990. A total of 927 aquatic invertebrates representing 37 taxa was identified. Over all samples, 45% of the aquatic invertebrates extracted were Chironornidae (samples ranging from 19-76%), 28% Trichoptera (ranging 11-49%), and 16% Ephemeroptera (ranging 2-42%). The dominant chironomid was Eukiefferiella sp., although Cricotopus spp. were also relatively abundant in some samples. Cased caddisflies were the main Trichoptera in all samples, but no one taxon was consistently dominant. Plecoptera comprised 0-20% of invertebrates in the faeces. In most samples collected below Tree Trunk Gorge, chironomids comprised ~61% of individuals recorded in the faeces, whereas above the gorge they comprised ~40% in any sample. Overall, the diet of Blue Duck on the Tongariro River in December 1990 was variable in terms of the proportions of species and the number of invertebrates that were consumed. This has also been shown in studies of Blue Duck diet on other rivers.