Meeting Abstract

P2.125  Wednesday, Jan. 5  Aggressive Behavior and Brain Morphologies in Clonal Rainbow Trout Lines (Oncorhynchus mykiss) with varying Domestication Histories CAMPBELL, J.M.**; THORGAARD, G.*; Washington State University Pullman; Washington State University Pullman campbell9@wsu.edu

Salmonids are valued around the world as a recreational icon, a food source and as research models. Hatchery rearing has subjected many trout and salmon populations to altered human-designed environments. The domestication process has been shown to cause behavior and morphological changes in many species. Three major questions are: How fast can it work, what percent of change is genetic vs. environmental in origin, and can specific genes associated with domestication be identified? To help untangle these questions our investigation is utilizing strains of clonal rainbow trout established with varying degrees of domestication history. We raised 3 male clonal lines in the same barren hatchery environment and subjected them to a mirror-elicited challenge situation. Preliminary results for three lines {one wild (WR), one semi-wild (SW) and one domestic (AR) are presented (n=30 individuals per line)}. Non-parametric Kruskal-wallis tests show significant differences in 4 major behaviors; frontal/swimming displays (P=0.0066), escape behavior (P<0.0001), freezing (P=0.0028) and swim against the mirror (P<0.0001). External measurements of 5 brain regions (i.e. telencephalon, olfactory bulb, optic tectum, hypothalamus and cerebellum) were taken using an ellipsoidal protocol. AR had a significantly smaller brain in all regions. We are also currently analyzing 3 more male lines with similar backgrounds and an out-bred strain. Future studies will raise the lines in hatchery and enriched environments, look for internal morphological and neurobiological brain changes, and conduct genetic analysis of domestication-related traits through QTL mapping.