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Historical background: Study of plankton communities of New Zealand waters has been neglected in the past. The various expeditions which have collected in the area have mostly concentrated on dredging, shore collecting and bathypelagic programmes. Even the earliest expeditions, dateing from the voyages of Cook, recorded superficial observations of plankton organisms. However, the first serious observations were the descriptions by Dana (1850's), of pelagic crustaceans from the collections of the U.S. Exploring Expeditions (1840). Then in the winter of 1874, H.M.S. "Challenger" made a number of tow-nettings in the Tasman Sea and the reports of the expedition together comprise the first comprehensive account of the plankton of the area.

Whole document restricted, see Access Instructions file below for details of how to access the print copy. / The structure and function of benthic invertebrate communities in the Waitakere River, a kauri forest stream ecosystem, was studied in association with physicochemical parameters from May 1973 until March 1976. Emphasis was placed upon life histories of the dominant species, so that changes in community structure along the stream could be characterised. Analysis of vegetation along the forested watercourse showed a predominance of podocarps and kauri (Agathis australis) in the canopy, with tree ferns dominating in the subcanopy. As the stream flowed into open farmed areas, algal blooms, which were mainly present in summer in some forested sites, became more widespread and persistant. These appeared to influence the composition of the invertebrate communities. Physicochemical analyses of water from several sites in the Waitakere River and its tributaries (from January to December 1974, and in July 1975 and February 1976) provided no evidence that algal blooms could be associated with nutrients derived from agriculture. In the classification of Williams (1964) the waters were "calcium poor" (generally <8.0 g/m3) and intermediate between "soft" and "medium hard" (alkalinity 15-44 g/m3). However, they were comparatively rich in silica (14-35 g/m3), sodium (17-25 g/m3) and chloride (25-39 g/m3). The association between physicochemical variables was tested by correlation matrix analysis. Two distinct groups were formed. Group A variables (temperature, sodium, conductivity, alkalinity, hardness, chloride and potassium) were positively correlated with each other, but negatively correlated with precipitation, whereas group B variables (manganese, iron and sulphate) were positively correlated with turbidity. A summer groundwater influence appeared to provide maximum values for group A variables, and increased turbidity during high rainfall (winter) produced maximum values for group B variables. The invertebrate fauna was surveyed throughout the watershed, and studied intensively at four sites (two in open farmland and two in forest) for 12 months. Separation of most invertebrate groups to species level provided 144 taxa, almost three times the number in previously published faunal lists for New Zealand streams, but comparable with those obtained in the Northern Hemisphere. Aspects of the life histories of the following 19 taxa were investigated: Potamopyrgus antipodarum (Gastropoda : Hydrobiidae), Paracalliope fluviatilis, (Amphipoda : Eusiridae), Coloburiscus humeralis (Ephemeroptera : Siphlonuridae), Zephlebia nodularis, Atalophlebioides sepia, Deleatidium lillii, D. myzobranchia, Deleatidium sp C, Deleatidium sp E (Ephemeroptera : Leptophlebiidae), Zelandobius furcillatus (Plecoptera : Gripopterygidae), Hydora nitida (Coleoptera : Elmidae), Maoridiamesa harrisi,? Austrocladius sp., Paratanytarsus agameta (Diptera : Chironomidae), Austrosimulium australense (Diptera : Simuliidae), Aoteapsyche colonica (Trichoptera : Hydropsychidae), Oxyethira albiceps (Trichoptera : Hydroptilidae), Pycnocentrodes spp and Olinga feredayi (Trichoptera : Sericostomatidae). Most of these had poorly synchronised, indistinct life cycles which could not be classified using the system of Hynes (1970) for temperate Northern Hemi sphere streams The most diverse communities occurred in the rapidly flowing, cool tributaries of the Waitakere River, dominated by insects with long life cycles. Downstream the communities were dominated by non-insect species, or insect species with rapid life cycles and a seasonal occurrence. Many of these appeared to be associated with algal blooms. A black polythene artificial canopy (44 m2) was placed over an area of the lower Waitakere River prone to algal blooms, to investigate the effect of algal removal induced by shading. Groups which declined in abundance under the canopy were Chironomidae and Hydroptilidae, while drift filtering species (Aoteapsyche colonica and Austrosimulium australense) increased in number under the canopy. Other taxa (Pycnocentrodes spp., Potamopyrgus antipodarum and Elmidae larvae) remained equally abundant in shaded and non-shaded areas. The possible contribution of species colonizing such "new" habitats through drift and adult flight was investigated. Invertebrates of the Waitakere River and its tributaries differed from those of temperate Northern Hemisphere streams in taxonomic composition, trophic structure (relative lack of "shredding" species), life history patterns and the presence of spatial and temporal overlap of related species (members of the genus Deleatidium). It is suggested that most of these characteristics occur throughout New Zealand, and are related to the types of detritus entering New Zealand streams, and the effects of long geological isolation.

Forty-five species of harpacticoid copepod (twenty-eight of them new), from sixteen genera and seven families, are described from New Zealand. The species were collected from a wide variety of freshwater habitats as well as from coastal and inland brackish water bodies and from terrestrial habitats with thin water films. Two new genera, Australomoraria and Taneroa, are described from within the Family Canthocamptidae, a family which contains the majority of species, and the genus Antipodiella Brehm, 1928, is resurrected, Keys to families, genera and species are given where applicable. The origins and relationships of the freshwater harpacticoid fauna are considered, together with its ecological and geographical distribution within New Zealand. / Whole document restricted, but available by request, use the feedback form to request access.

The static and dynamic distribution patterns of ichthyoplankton were investigated over a 4 year period (1981 - 1985) off the coast of Leigh, on the northeastern coast of New Zealand. Emphasis was given to horizontal and vertical distributions, and these were described on scales encompassing broad areas of the outer Hauraki Gulf and smaller areas of 1 - 100m. The ages of these small fish were also investigated by examining daily increments in the otoliths, and this allowed a more complete interpretation of distribution patterns. Sampling that was carried out at different distances from the mainland identified major differences in the distribution patterns of individual species. For example, pilchards were caught in high densities right across the continental shelf, whereas morid cod were restricted to the outer edge of the shelf. The most intensive investigations were carried out over the Summer months and these revealed large differences in the abundances of species. For instance, few bothids and triglids were captured in December, while large numbers were caught in January. The spawning activity of adults and broad scale differences between water masses were probably responsible for these distance and time related patterns. Large differences in the densities of ichthyoplankton were found at different localities within each area of the continental shelf (e.g. close to the mainland). Furthermore, detailed investigations of abundances at a single locality over a three day period showed large changes. These changing distribution patterns were related to the dynamics of localized hydrological features (e.g. tidally induced gyres). The presence of islands over the continental shelf also influenced the distribution of small fish. Some species were only found near land, regardless of the distance from the mainland. From ichthyoplankton hauls and direct observations made using SCUBA, it is argued that the behaviour of ichthyoplankton may have a strong influence on their distribution patterns. For example, tripterygiids and gobiesocids of a variety of ontogenetic forms were observed to aggregate and maintain their position in the shallow areas of rocky reefs. Large differences were found in the vertical distributions of fish and this was true in water columns from 1 - 40m in depth. Ichthyoplankters of a number of species had different depth distributions. Some species were consistently found near the surface (e.g. hemiramphids & mugilids) or near the bottom (e.g. eleotrids). For species found throughout the water column during the day, it was suggested that biological and physical stratification (e.g. thermoclines) strongly influenced relative densities at each depth stratum. Some species (especially engraulids & scombrids) migrated toward the surface at night. Migration patterns varied for each species and among times. The latter patterns were related to ambient light levels which changed with the phase of the moon. Small scale structure in the pelagic environment influenced the distribution of fish. Large numbers of fish were found around drift algae and when experimental algae were left to drift, small fish of several species (e.g. Monacanthids) were quickly attracted to it. A number of species were abundant in surface waters, but did not associate with drift algae (e.g. engraulids). For fish that were found around drift algae, the association may be important as a source of shelter and food. There was considerable seasonality in the occurrence of fish species around algae, and the abundance of total drift algae. Drift algae were most abundant over Spring and early Summer. The movements and accumulation of algae are discussed in relation to the potential influence it has on recruitment patterns of fish in nearshore environments. The distribution patterns of small fish were strongly influenced by the surface slicks of internal waves. Densities of small fish, drift algae, and zooplankton were higher in slicks than in rippled water adjacent to them. Slicks moved at 0.5 - 1.25 km per hour in the direction of shore. A consequence of aggregation in slicks, therefore, is that small fish may be transported onshore. It is suggested that the accumulation of zooplanktonic food in slicks may be important for the feeding of ichthyoplankters. Many of the fish found in surface waters, be it in open water or around drift algae, had adult fin-ray counts and were not considered to be larvae, according to current definitions. From information on the age and size of these fish it is suggested that the capacity of fish to settle at a variety of ages and sizes has probably been underestimated. Furthermore, the occurrence of physical processes such as slicks may influence the duration of the planktonic phase and subsequent settlement rates of fish into nearshore environments. The major findings were used to provide an overall picture of what happens during the planktonic phase of some species (Chrysophrys auratus, Parika scaber & tripterygiids), and these case histories are discussed in relation to current hypotheses concerning the ecology of ichthyoplankton.

Despite advances of recent years no stable higher order classification of the Porifera has yet emerged. To address this problem, relationships at various taxonomic levels within the Order Hadromerida have been evaluated. Descriptions of new species of. Tethya, Aaptos and Polymastia from northern New Zealand are given in conjunction with a review and redefinition of specific diagnostic characters for these genera. A range of species, genera and families within the Hadromerida have been subjected to 18S rRNA sequencing. Using morphological and molecular sequence data together in phylogenetic analysis, the existing familial groups of the Hadromerida are confirmed and some rearrangement of genera is indicated following sequence alignment and comparison. These data serve as a baseline for molecular approaches to resolving relationships between other sponge groups. / Thesis now published as papers. Whole document restricted at the request of the author, but available by individual request, use the feedback form to request access.