New Zealand's Distinctive and Well-Known Freshwater Fish Fauna -- The Geographical Setting of New Zealand and Its Place in Global Geography -- New Zealand's Geological and Climatic History and Its Biogeographical Context -- A Conceptual Basis for Biogeography -- Some Essentials of Freshwater Fish Biogeography, Fish Life Histories, and the Place of Diadromy -- Data Sources for the Present Study -- Phylogenetic Lineages in the Fauna and the Evolution of Diadromy: A Broad Perspective -- Galaxias and Gondwana -- Broad-Scale, Macroecological Patterns, Ranges and Community Species Richness in the Fauna -- Pattern and Process in the Distributions and Biogeography of New Zealand Freshwater Fishes: The Diadromous Species -- Pattern and Process in the Distributions of Non-diadromous Species - 1: The Galaxias vulgaris Species Complex -- Pattern and Process in the Distributions of Non-diadromous Species 2: The 'Pencil-Galaxias' Species Group -- Pattern and Process in the Distributions of Non-diadromous Species 3: The Dune Lakes Galaxias -- Distribution, History and Biogeography of the Neochanna Mudfishes -- Distribution and Biogeography of the Non-diadromous Gobiomorphus Bullies -- A Biogeographical Synthesis: 1. The Big Picture -- Biogeographical Synthesis: 2. More Local Issues and Patterns -- A Biogeographical Synthesis 3: Issues of Diadromy, Diversification and Dispersal -- Some General Biogeographical Patterns in the Fish Fauna -- A More Global Perspective and a Final Summation. This book provides a synthesis of taxonomic and ecological information on New Zealand's freshwater fish fauna. New Zealand has been isolated in the southwestern Pacific Ocean since it separated from Gondwana during the Cretaceous period, some 80 million years ago. This prolonged geological isolation, combined with the islands' very vigorous geological history, impacted by oceanic submergence, tectonic activity, mountain building extreme volcanism, and great climatic variability, create a dynamic scenario within which the New Zealand biota, including its freshwater fishes, have evolved over millions of years. These impacts have contributed to a highly dynamic biological history with undoubted though little understood extinction and vigorous colonisation of the islands' fresh water. One of the key elements for understanding the origins and derivations of this fish fauna is that in all groups some or all of the species are diadromous, customarily spending a significant phase of their lives at sea. This has no doubt contributed in an important way the fauna's origins as well, there has been frequent loss of diadromous behaviours leading, to species that have abandoned their sea-migratory behaviours and which now complete their entire lives in fresh water. The distribution patterns reflect these changing habits, with diadromous species being broadly distributed but tending to be lowland in range, whereas the derived, non-diadromous species have narrower ranges, but are often found further inland and at high elevations. This book provides an ecological and historical synthesis of these divergent patterns across New Zealand's geography and history.