Date of Award


Publication Type

Master Thesis

Degree Name



Great Lakes Institute for Environmental Research


Daniel D. Heath


Biological sciences, Oncorhynchus tshawytscha, Conservation, Genetic load, Inbreeding, Inbreeding depression, Purging, Salmon




Strong evidence that shows inbreeding in many plants and animals can lead to detrimental effects at the level of the organism as well as the population. Inbreeding and its effects have been the focus of much attention in terms of conservation and captive rearing and breeding programs for many endangered species. Inbreeding depression (ID) is the fitness loss associated with individuals and populations that have experienced inbreeding. Surprisingly, ID studies within salmonids are not extensive. Here, I used inbred offspring of self-fertilized hermaphrodite parents to study the effects of ID in Chinook salmon ( Oncorhynchus tshawytscha ) at an extreme level of inbreeding. High levels of ID were found after a single generation of self-crossing, resulting in substantial fitness losses. The potential to purge genetic load from a population was shown to take place and the major genetic mechanism driving ID was due to expression of deleterious recessive alleles.