Volcanism and freshwater fish biogeography in the northeastern North Island of New Zealand

Major volcanic eruptions in the central North river systems by dispersing through the sea. However, some Island of New Zealand and, in particular, an eruption dated rivers, that were probably severely affected in their at  186, spread ignimbrite and volcanic ashes (tephra) headwaters, have lower elevation and more distant over a broad area, deposition of which caused major tributaries whose catchments escaped ash showers; these defaunation of affected habitats. However, riverine provided refuges for non-diadromous species which could freshwater fish faunas were undoubtedly affected far beyond recolonize upstream once rivers became inhabitable. In such the zones of ignimbrite deposition and ash settlement as a rivers the fish faunas are now a mix of diadromous and result of ash-laden floods moving down rivers. In areas non-diadromous species. where entire river systems were covered with ash, fish faunas