Date of Award

2012

Degree Type

Thesis

Degree Name

M.Sc.

Department

Great Lakes Institute for Environmental Research

First Advisor

Daniel D. Heath

Keywords

Biological sciences, Health and environmental sciences, Aquaculture, Chinook salmon, Conservation, Escapes, Genetics, Outbreeding depression

Rights

CC BY-NC-ND 4.0

Abstract

Wild Chinook salmon (Oncorhynchus tshawytscha ) populations could be adversely affected through reproductive interactions with escaping farmed salmon. To determine the reproductive ability of farmed Chinook salmon relative to wild, I compared sperm traits, as well as fertilization and reproductive success in competitive spawning channels. Farmed Chinook salmon males had greater sperm performance relative to wild males, and they were equally successful at competing for mates and fertilizing eggs. However, farm-sired offspring experienced lower survival to the fry stage, which could mediate any impact on the wild populations. Given that hybridization can lead to negative genetic effects via outbreeding, I also tested the theory of outbreeding depression in backcrossed hybrid (F2) Chinook salmon using fitness related traits. I found no evidence of outbreeding depression in Chinook salmon, which further suggests that the introgression of farmed genes into the wild would not result in negative fitness consequences for wild salmon populations.

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