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dc.contributor.advisorCloss, Gerry
dc.contributor.authorBruno, David O.
dc.date.available2019-02-19T21:07:05Z
dc.date.copyright2002-05-11
dc.identifier.citationBruno, D. O. (2002, May 11). Ecology of the giant kokopu (Thesis, Doctor of Philosophy). University of Otago. Retrieved from http://hdl.handle.net/10523/8980en
dc.identifier.urihttp://hdl.handle.net/10523/8980
dc.description.abstractThis study aimed to determine the distribution of giant kokopu, G. argenteus within the Lower Taieri Floodplain in New Zealand's South Island and then to examine various ecological aspects of this species including micro-habitat use, home range, activity patterns, flood movements, and dominance hierarchies. Significant populations of G. argenteus were found in small streams draining into the Taieri Floodplain but were rarely located from lentic waterbodies. G. argenteus were regularly found to exist with brown trout (Salmo trutta) in the same stream but co-existence at finer spatial scales was less common. In streams, giant kokopu used specific habitat types and maintained restricted home ranges during base flow conditions. Activity patterns of giant kokopu were recorded using a novel; remote, radiotelemetry system. Distinct differences in activity and habitat use were observed during the day and night, and between summer and winter. During winter, giant kokopu were always concealed amongst cover during the day and located in open, low velocity habitats at night. During summer giant kokopu were frequently active during both light and dark periods with fish showing a marked increase in the use of shallower and higher velocity habitats, particularly at night. A limited study on giant kokopu diet conducted during summer and winter revealed that both aquatic and terrestrial items were important components in the diet. During high discharge events, fish displayed a range of behaviours with some fish exhibiting homing capabilities. Reasons for moving during floods appear to be quite complex and may not necessarily be related to the magnitude of the discharge. In many instances individual giant kokopu exhibited adaptive behaviours in response to high flows. Behaviours supporting this view included fish that moved upstream during the peak discharge period, fish that did not move during the largest floods and fish that made micro-movements ( < 10 m) from regular cover locations to low velocity habitats. The social interactions and spatial distributions of giant kokopu investigated over a brief period suggested that a size related dominance hierarchy was evident within stream pools during summer. The feeding and social behaviour exhibited by giant kokopu during the day appeared to correspond with those exhibited by salmonids and other drift feeding fish in the Northern Hemisphere.en_NZ
dc.format.mimetypeapplication/pdf
dc.language.isoenen_NZ
dc.publisherUniversity of Otago
dc.titleEcology of the giant kokopuen_NZ
dc.typeThesisen_NZ
dc.date.updated2019-02-19T21:06:44Z
thesis.degree.disciplineZoologyen_NZ
thesis.degree.nameDoctor of Philosophyen_NZ
thesis.degree.grantorUniversity of Otagoen_NZ
thesis.degree.levelPhDen_NZ
otago.openaccessOpenen_NZ
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