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McMaster, Aidan Clark

University of British Columbia

Understanding how morphology is shaped by captive breeding and rearing of fish is becoming increasing important for policy-making surrounding the conservation of aquatic species, as hatchery supplementation becomes more and more commonplace and the potential for impacts on wild populations grows. Therefore, the objective of this thesis was to explore how genetics and environment shape the morphological phenotypes of domestic-wild hybrid salmonids. First, I used photos of F2 hybrid rainbow trout parr after a single growing season in a semi-natural environment to determine whether “domestic” or “wild” phenotypes predominate under these conditions. I found differences in overall body shape, particularly in the head and deepness of the body between the domestic and wild fish. Some phenotypes in the F2s were more similar to those of one or the other of the grandparents reared in hatchery conditions, and others were entirely different, likely due to the differences in food availability, presence of predation, water velocity, etc. in the semi-wild environment compared to a hatchery environment. Next, I used photos of F2 offspring of domestic and wild strains of coho salmon to do a similar analysis, which revealed an extremely fast-growing group of juveniles. I then used next-generation genomic sequencing (PoolSeq) to attempt to find SNPs correlated with this fast growth trait. I found three large regions of differentiation between the fast growing and slow growing F2 fish, with enrichment for processes such as musculoskeletal development, omega peptidase activity, and folate transmembrane transport. The results of my first chapter indicate that the environment has extremely large impacts on morphological phenotypes; however, as shown by my second chapter, genotype can create drastic differences in morphology when rearing conditions are identical. The results of this thesis illustrate the interacting effects of genetics and environment on morphological phenotypes in salmonids.

Text

2023-09-01

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/85772

Zoology

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/