title: Distribution and abundance of fish and crayfish in a Waikato stream in relation to basin area

authors: Hicks, Brendan J.

subjects: native fish

abstract: The aim of this study was to relate the longitudinal distribution of fish and crayfish to increasing basin area and physical site characteristics in the Mangaotama Stream, Waikato region, North Island, New Zealand. Fish and crayfish were captured with two-pass removal electroshocking at 11 sites located in hill-country with pasture, native forest, and mixed land uses within the 21.6 km2 basin. Number of fish species and lineal biomass of fish increased with increasing basin area, but barriers to upstream fish migration also influenced fish distribution; only climbing and non-migratory species were present above a series of small waterfalls. Fish biomass increased in direct proportion to stream width, suggesting that fish used much of the available channel, and stream width was closely related to basin area. Conversely, the abundance of crayfish was related to the amount of edge habitat, and therefore crayfish did not increase in abundance as basin area increased. Densities of all fish species combined ranged from 17 to 459 fish 100 m-2, and biomass ranged from 14 to 206 g m-2. Eels dominated the fish assemblages, comprising 85-100% of the total biomass; longfinned eels the majority of the biomass at most sites. Despite the open access of the lower sites to introduced brown trout, native species dominated all the fish communities sampled.

text: Distribution and abundance of fish and crayfish in a Waikato stream in relation to basin area The aim of this study was to relate the longitudinal distribution of fish and crayfish to increasing basin area and physical site characteristics in the Mangaotama Stream, Waikato region, North Island, New Zealand. Fish and crayfish were captured with two-pass removal electroshocking at 11 sites located in hill-country with pasture, native forest, and mixed land uses within the 21.6 km2 basin. Number of fish species and lineal biomass of fish increased with increasing basin area, but barriers to upstream fish migration also influenced fish distribution; only climbing and non-migratory species were present above a series of small waterfalls. Fish biomass increased in direct proportion to stream width, suggesting that fish used much of the available channel, and stream width was closely related to basin area. Conversely, the abundance of crayfish was related to the amount of edge habitat, and therefore crayfish did not increase in abundance as basin area increased. Densities of all fish species combined ranged from 17 to 459 fish 100 m-2, and biomass ranged from 14 to 206 g m-2. Eels dominated the fish assemblages, comprising 85-100% of the total biomass; longfinned eels the majority of the biomass at most sites. Despite the open access of the lower sites to introduced brown trout, native species dominated all the fish communities sampled.

year: 2003-06-01

title: An Integrated Stratigraphy of Tauranga Harbour

authors: MacPherson, David

subjects: Tauranga

abstract: Tauranga Basin is a Quaternary basin filled with successions of terrestrial and coastal sediments. The largest feature of Tauranga Basin is Tauranga Harbour, a 570km2 estuary. This is home to the Port of Tauranga, New Zealands largest export port. Studies conducted following an initial study by Davis and Healy (1993) have found complex distributions of the sediments within the dredged shipping channel. This research used 86 vibracores and limited seismic data to identify four main facies within the shallow subsurface of the dredged channel and establish their distribution.
Four facies were identified within the shallow subsurface: the Volcanic Sand facies, a silt to fine sand volcaniclastic succession; the Silt facies, a silt to very fine sand lacustrine deposit; the Coastal Sands facies, a medium to coarse coastal sand deposit; and the Pumiceous Sand Facies, a medium to coarse sand succession with abundant pumice.

Within the dredged shipping channel, the Volcanic Sands and Silt facies outcrop at the surface, and appear as ridges in the subsurface. Draped over these ridges is the Coastal Sands facies, which in some cores is overlain by Pumiceous Sands. The Volcanic Sands facies represents a succession of tephra deposits, with some reworking between depositional events. In the Maunganui Roads region of the harbour this is overlain by the lacustrine Silt facies, formed from the reworking of the Volcanic Sands. The region was then inundated by the Holocene marine transgression, leading to the deposition of the Coastal Sands facies, sourced from offshore. This Coastal Sands facies is then overlain in areas by Pumiceous Sands, small mobile sand waves that exist within the shipping channel. These are formed following the erosion of ignimbrite cliffs around the harbour, with some input from the outside the harbour. This represents a change in source for sedimentation in the harbour.

An updated model of the paleogeographic development of the harbour is presented, using data from this and other studies. This model shows the presence of a braided river flowing through Stella Passage, before the development of a lake and the subsequent Holocene marine transgression leading to the evolution of the sand spit and Matakana barrier island.

text: An Integrated Stratigraphy of Tauranga Harbour Tauranga Basin is a Quaternary basin filled with successions of terrestrial and coastal sediments. The largest feature of Tauranga Basin is Tauranga Harbour, a 570km2 estuary. This is home to the Port of Tauranga, New Zealands largest export port. Studies conducted following an initial study by Davis and Healy (1993) have found complex distributions of the sediments within the dredged shipping channel. This research used 86 vibracores and limited seismic data to identify four main facies within the shallow subsurface of the dredged channel and establish their distribution.
Four facies were identified within the shallow subsurface: the Volcanic Sand facies, a silt to fine sand volcaniclastic succession; the Silt facies, a silt to very fine sand lacustrine deposit; the Coastal Sands facies, a medium to coarse coastal sand deposit; and the Pumiceous Sand Facies, a medium to coarse sand succession with abundant pumice.

Within the dredged shipping channel, the Volcanic Sands and Silt facies outcrop at the surface, and appear as ridges in the subsurface. Draped over these ridges is the Coastal Sands facies, which in some cores is overlain by Pumiceous Sands. The Volcanic Sands facies represents a succession of tephra deposits, with some reworking between depositional events. In the Maunganui Roads region of the harbour this is overlain by the lacustrine Silt facies, formed from the reworking of the Volcanic Sands. The region was then inundated by the Holocene marine transgression, leading to the deposition of the Coastal Sands facies, sourced from offshore. This Coastal Sands facies is then overlain in areas by Pumiceous Sands, small mobile sand waves that exist within the shipping channel. These are formed following the erosion of ignimbrite cliffs around the harbour, with some input from the outside the harbour. This represents a change in source for sedimentation in the harbour.

An updated model of the paleogeographic development of the harbour is presented, using data from this and other studies. This model shows the presence of a braided river flowing through Stella Passage, before the development of a lake and the subsequent Holocene marine transgression leading to the evolution of the sand spit and Matakana barrier island.

year: 2016

title: Action for improvement in our own contexts

authors: Bruce Ferguson, Pip

subjects: education

abstract: Discusses: The pedagogy of Paulo Freire – importance of emancipatory, not ‘banking’, education. Who needs emancipatory education in NZ, and why? Consideration of issues affecting Māori success in the New Zealand education system.

text: Action for improvement in our own contexts Discusses: The pedagogy of Paulo Freire – importance of emancipatory, not ‘banking’, education. Who needs emancipatory education in NZ, and why? Consideration of issues affecting Māori success in the New Zealand education system.

year: 2012