Date of Award

2019

Publication Type

Master Thesis

Degree Name

M.Sc.

Department

Great Lakes Institute for Environmental Research

First Advisor

Oliver Love

Second Advisor

Christina Semeniuk

Keywords

climate change, environmental match, maternal stress, salmon, thermal stress

Rights

info:eu-repo/semantics/openAccess

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Abstract

Climate change is increasing global water temperatures, and by altering temperatures, is subsequently impacting aquatic life, particularly ectothermic fish. When mothers encounter environmental stressors such as elevated temperatures during follicular recruitment (maternal stress), resultant offspring often have altered phenotypes. Recent studies suggest that this maternal stress signal may prepare offspring for a similarly stressful environment (environmental match). I applied the environmental match hypothesis to investigate whether a maternal stress signal can prepare offspring to cope in a stressful environment. Specifically, I exposed Lake Ontario Chinook salmon (Oncorhynchus tshawytscha) eggs to a biologically relevant maternal stress signal (1000ng/mL cortisol or control). We split and reared these dosed groups at temperatures indicative of current and future temperature conditions (+3°C). Then we investigated the interactive effects of thermal and maternal stress on offspring early survival, early morphology, and thermal tolerance (i.e., CTMax and energetic responses to temperature spikes). Overall I found that rearing temperature was an overriding modulator of offspring phenotype and performance. Offspring raised in elevated temperatures had lower early survival, were smaller and had a higher acute tolerance. Prenatal cortisol did not definitively modulate offspring phenotype or performance under elevated rearing temperatures. My thesis provides evidence for the role of predictive adaptive responses, as offspring who were reared in elevated temperatures had higher thermal tolerance at parr stage. Applying the environmental context of intergenerational plastic mechanism such as maternal stress remains imperative as the world continues to rapidly change under the effects of human-mediated climate change.

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