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dc.contributor.advisorCloss, Gerry
dc.contributor.authorTrotter, Morgan John
dc.date.available2016-05-12T02:17:26Z
dc.date.copyright2016
dc.identifier.citationTrotter, M. J. (2016). Juvenile trout survival and movement during the summer low flow abstraction period in the Lindis River, Central Otago (Thesis, Master of Science). University of Otago. Retrieved from http://hdl.handle.net/10523/6450en
dc.identifier.urihttp://hdl.handle.net/10523/6450
dc.description.abstractSurvival and movement of juvenile brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) were investigated during low flow conditions in the Lindis River, Central Otago. High levels of abstraction from this river result in drought-like events on an annual basis. Over two years, during the summer low flow period >1000 juvenile trout were marked with passive integrated transponder (PIT) tags. Their movements were tracked using mobile PIT tag antenna. To detect emigration and losses to an irrigation channel stationary PIT tag antenna were also positioned on the main-stem river and on the channel. After PIT tagging the study area was subjected to extreme low flow conditions in both years. Mark-recapture model analysis indicated that only a small proportion of the sample population survived the low flow events; 0.34 (95 % CI: 0.21-0.50) in year one and 0.29 (95% CI: 0.18-0.39) in year two. Water temperatures in flowing water remained within salmonid tolerance levels. Low survival rates were primarily attributed to high levels of predation and the lowest survival probabilities were associated with reduced cover for juvenile salmonids. Fish that did die from heat stress in disconnected and drying pools were immediately removed by scavengers, indicating that any dead fish observed during prolonged low flow conditions are likely to represent a small proportion of the total mortality experienced. Potential fish movement from stressful habitat during the both years was constrained by drying reaches, and an irrigation intake structure. Some sample fish displayed considerable movement along the remaining fragmented river corridor, presumably in an attempt to find refuge habitat.
dc.format.mimetypeapplication/pdf
dc.language.isoen
dc.publisherUniversity of Otago
dc.rightsAll items in OUR Archive are provided for private study and research purposes and are protected by copyright with all rights reserved unless otherwise indicated.
dc.subjectJuvenile
dc.subjecttrout
dc.subjectsurvival
dc.subjectmovement
dc.subjectflows
dc.subjectpredation
dc.subjectsummer low flow
dc.subjectwater abstraction
dc.titleJuvenile trout survival and movement during the summer low flow abstraction period in the Lindis River, Central Otago
dc.typeThesis
dc.date.updated2016-05-11T23:38:46Z
dc.language.rfc3066en
thesis.degree.disciplineZoology
thesis.degree.nameMaster of Science
thesis.degree.grantorUniversity of Otago
thesis.degree.levelMasters
otago.openaccessOpen
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