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The effects of embryonic incubation temperature on subsequent development, growth, and thermal tolerance through early ontogeny of white sturgeon

University of British Columbia

An organism’s phenotypic characteristics can be altered by environmental variations experienced during embryonic development. These changes can persist into adulthood. Increasing global temperatures are a current concern that may be particularly acute for species already threatened or endangered, such as the white sturgeon, Acipenser transmontanus. Given scant information on the effects of early embryonic temperatures on subsequent physiological parameters such as thermal tolerance, development, and growth in this species, the effects of global climate change on the future of white sturgeon populations is uncertain. To address this, white sturgeon embryos were incubated at 12, 15, and 18 °C until hatch, after which fish were reared at a common 15 °C for 80 days post-hatch. I conducted acute thermal tolerance tests through early ontogeny to determine how relative thermal tolerance (CTmax) changed and differed during this period while also sampling and evaluating various morphometric characteristics to determine the effects of embryonic temperatures on growth and development. Embryonic incubation at 12 °C with subsequent rearing at 15 °C increased larval development rate, growth rate, and the development of thermal tolerance; however, once developed CTmax averaged 29.9 for all embryonic rearing temperatures. For white sturgeon, embryonic temperatures appear to have discernable effects on growth and development up to 80 days post-hatch but not on thermal tolerance.

Text

2019-06-24

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/70736

Zoology

University of British Columbia

UBCV

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