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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Growth and Movement in Brown Trout (Salmo trutta) in two Norwegian Rivers

Skjellevik, Stine Marie January 2012 (has links)
In the present study, using stream-dwelling brown trout (Salmo trutta) as a model species, movement through the summer and autumn in two large Norwegian rivers, River Glomma and River Gudbrandsdalslågen, was observed. In addition fish from each river were sampled for age and growth analysis. The aim of the study was to test for which individual characteristics (sex, body mass, body condition factor, tagging site and cohort) that influenced movement and to test for correlations between growth rates (both immature and mature) and movement (movement during the growth season and spawning migration) on a large spatiotemporal scale. Model selection showed that body condition was negatively related to movement during the growth season and that there was a difference in movement activity between the two rivers. Female body size had a positive effect on the activity level shown for movement during the growth season and spawning period; however no such relationship was found for males. As this relationship has not been shown before in salmonids, the reason for this pattern remains unknown. However, one might speculate that it is related to differences between the two sexes in size-specific energy requirements associated with spawning. Neither movement during the growth season nor spawning migration could be predicted from growth rates experienced as juveniles. This indicates that variation in movement among individuals is not temporally consistent throughout life in brown trout.

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