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Gewählte Master / Diploma Thesis:

Jamie Lee Morgan (2020): Brown trout spawning activity and recruitment The influence of temperature and discharge in Alpine headwater streams.
Master / Diploma Thesis - Institut für Hydrobiologie und Gewässermanagement (IHG), BOKU-Universität für Bodenkultur, pp 99. UB BOKU obvsg FullText

Data Source: ZID Abstracts
Abstract:
Rivers and streams experience yearly fluctuations in the recruitment and structure of brown trout (Salmo trutta) populations. Rising global temperatures have been shown to directly affect the thermal and hydrological regimes of Alpine rivers. In turn, these environmental changes can influence trout spawning behavior. This thesis investigated the degree to which temperature and discharge influenced the spawning and recruitment of brown trout in small Alpine streams. Three streams located in the Piesting headwaters of Lower Austria were selected for the study. A combination of redd counts and stock assessments were used to identify the spawning behavior and recruitment success of the trout populations within these streams. Redd counts were used to quantify the onset, duration, and intensity of spawning activity. Stock assessments were used to evaluate the recruitment and age structure of the population. Water temperature and discharge data were used for modeling the environmental conditions of the streams. The relationship between mean summer water temperature and spawning activity was explored. A bivariate approach was also used to investigate how spawning activity parameters influenced population recruitment. Additionally, correlations between maximum discharge during different YOY life stages and recruitment were examined. Water temperature showed an upward trend during the study but did not significantly affect the onset or duration of spawning. However, increased temperature was linked with lower redd density. This may have impacted the population, as redd density was positively correlated with successful recruitment. There was also high probability that discharge during the spawning period was positively correlated with recruitment, whereas high flows during incubation were negatively correlated with recruitment success. The acquired knowledge provided better understanding of brown trout population dynamics and nursery habitat use in small headwater streams.

Beurteilende(r): Schmutz Stefan
1.Mitwirkender: Pinter Kurt

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