Date of Award


Document Type

Open Access Dissertation

Degree Name

Doctor of Philosophy in Biological Sciences (PhD)

Administrative Home Department

Department of Biological Sciences

Advisor 1

Casey Huckins

Advisor 2

Amy Marcarelli

Committee Member 1

David Flaspohler

Committee Member 2

Troy Zorn


Over the last 150 years, many of the native migratory salmonid populations in North America have declined or been extirpated, and their native habitats have been significantly altered. Life history variation within and among migratory fish populations plays an important role in their persistence when faced with changing habitat conditions. One of the most extreme life history events in salmonids is the movement from lotic to lentic habitats, a migration that can span long distances and different habitat types. Understanding the factors affecting migratory life histories expressed by individuals within a population play an important role in dynamics and habitat requirements of the whole population. Here, I investigate three primary factors that contribute to an individual fishes’ “decision” to migrate: genetics, environmental conditions, and individual body condition. In rainbow trout Oncorhynchus mykiss of the Shasta River, California we found distinct genetic structure among subpopulations in spatially separate habitats. Within one of those population segments we detected partial migration in which some individuals migrate, but others do not. We found that increased in daily mean water temperature were associated with upriver migration of adult coaster brook trout Salvelinus fontinalis in the Salmon Trout River, Michigan. In the Pilgrim River, Michigan we documented a previously unrecognized population of migratory brook trout. These results provide information critical to understanding the ecology of these at-risk populations and broaden our understanding of migratory behavior in general. The methodologies we developed to quantify movement data in the context of migratory life histories are applicable to other systems where further understanding of the drivers of migratory life history variation is needed.