Thesis
Domestication, aggressive behavior and brain size in rainbow trout (Oncorhynchus mykiss)
Washington State University
Master of Science (MS), Washington State University
2012
Handle:
https://hdl.handle.net/2376/101691
Abstract
In the Pacific Northwest fish hatcheries have been widely used to help address declines of wild fish and meet the rising demand. The domestication process has been shown to cause behavior changes and reduced brain size in many species. Three major questions were addressed in this thesis based on studies of 11 diverse genotypes. The questions were: What are the mirror-elicited aggressive tendencies in rainbow trout with varying degrees of domestication? How does brain size relate to domestication level in rainbow trout? Finally, is there a relationship between aggressive behavior and brain size among domesticated and wild trout? We performed principal component analyses (PCA) on thirteen behavioral and brain/body size variables and detected several behavioral syndromes among the trout genotypes. PCA I on six male clonal lines in which various domestication histories were analyzed had the most pronounced results. Two behaviors "freeze and escape" correlated to high domestication; "display" behavior was correlated to wild type and "sam/swim against the mirror" was correlated to semi-wild and domestic lines. To exclude body size as a factor from brain size we used SAS Proc Mixed and found two brain sizes (i.e. total brain volume and olfactory volume) that were significantly related to domestication level. The domesticated lines had larger volumes in both total brain size and olfactory region over their wild counterpart (p=<0.0001). PCA II compared the 13 variables from among three Swanson hybrid genotypes in which both males and females were included. In this analysis the sam behavior became a major eigenvalue with the brain components in PC1 and PC3; display and optic tectum eigenvectors were also found to be correlated. No gender difference was detected but there was a suggestion for a "family" parental male contribution factor which should be analyzed further. The differences and behavioral syndromes identified in this study among the clonal lines demonstrated that future studies could conduct genetic analysis of domestication-related traits through QTL mapping along with physiological and stress-related traits.
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Details
- Title
- Domestication, aggressive behavior and brain size in rainbow trout (Oncorhynchus mykiss)
- Creators
- Janet M. Campbell
- Contributors
- Gary Thorgaard (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Biological Sciences, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525290801842
- Language
- English
- Resource Type
- Thesis