Date of Award

2011

Degree Type

Thesis

Degree Name

M.A.Sc.

Department

Biological Sciences

First Advisor

Pitcher, Trevor (Biological Sciences)

Keywords

Biology.

Rights

CC BY-NC-ND 4.0

Abstract

Sperm competition is an important determinant of male reproductive success. This thesis examined sperm competition in the context of the alternative reproductive tactics (jacks and hooknoses) of Chinook salmon (Oncorhyncus tshawytscha). I found that jacks had relatively larger gonads and had higher sperm velocity than hooknoses. I also examined competitive fertilization success of the two tactics using a more realistic spawning microenvironment, in the presence of ovarian fluid. I found a significant increase in sperm velocity when activated in ovarian fluid compared to river water for both reproductive tactics and jacks were more successful at siring offspring in sperm competition than hooknoses in water but not in ovarian fluid. I found a significant positive relationship between sperm velocity and competitive fertilization success in water but not ovarian fluid. These results have implications for studies of sperm competition in taxa that do not take into account the female role in reproduction

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