Interactions of the Native and Alien Faunas of New Zealand and the Problem of Fish Introductions

New Zealand possesses a small and unsaturated but peculiar indigenous freshwater fish fauna. In addition, a considerable variety of introduced species is now in competition with the native species and evidence suggests that this is causing depletion of the native fauna. It is considered that low saturation and high isolation of the New Zealand fauna has produced species with low competitive ability. The largely predatory introduced game fishes are of continental origin and their superior competitive ability is leading to competitive displacement of the native species.