Fishpasses For Native Freshwater Fishes in New Zealand: Changing Attitudes, Politics, and Approaches
Fish Passage Policy and Technology: Proceedings of a Symposium
American Fisheries Society
New Zealand is one of the most isolated land masses, of any significant size in the world. There are only 27 species of native freshwater fish and 17 species are diadromous. The remainder are recent derivatives of these species. Polynesian settlement approximately 1000 years B.P. resulted in a wave of extinction of bird life and the removal of much forest. Freshwater fish then assumed importance for inland tribes as significant sources of protein and fat. European colonization began in the 19th Century and completed removal of most lowland rain forests for grassland and pastoral farming. A wide range of freshwater fishes were introduced, primarily from North America and Europe. Native fish provided forage for trout or were 'controlled' as predators. One species became extinct, others are rare. Increasing environmental awareness and a commitment to honoring a treaty which guaranteed Fisheries Rights of the Maori people has seen a resurgence of interest in conservation and enhancement of native freshwater fish. This includes construction of specialized fish passes to restore populations of diadromous species. The basic design principles of passes for climbing fishes and elvers are described.