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Research

Behavioural response to hypoxia

Freshwater pond snails inhabit environments subjected to daily and seasonal periods of low oxygen (hypoxia). Embryos of Helisoma trivolvis, a pulmonate pond snail are found throughout North America and are encapsulated within an egg capsule, contained within an egg mass. These embryos exhibit a robust rotational behaviour during hypoxia that is hypothesized to stir the capsular fluid to enhance delivery of oxygen during periods of hypoxia. I investigated the response of this behaviour to hypoxia to understand how it enhances embryo survival.
Key publications:
  • Shartau RB, Harris S, Boychuk EC and Goldberg JI. 2010. Rotational behaviour of encapsulated pond snail embryos in diverse natural environments. Journal of Experimental Biology. 213(12): 2086-2093.
  • Shartau RB, Tam R, Patrick S and Goldberg JI. 2010. Serotonin prolongs survival of encapsulated pond snail embryos exposed to long-term anoxia. Journal of Experimental Biology. 213(9): 1529-1525.
  • Goldberg JI, Doran SA, Shartau RB, Pon JR, Ali DW, Tam R and Kuang S. 2008. Integrative biology of an embryonic respiratory behavior in pond snails: the “embryo stir-bar hypothesis” (Invited review). Journal of Experimental Biology. 211(11): 1729-1736.
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Strategies of acid-base regulation during high CO2

Many aquatic environments experience high CO2, ranging from 2 - 8 kPa (~20,000 - 80,000 uatm) such as aquaculture ponds and tropical freshwaters of the Mekong and Amazon Rivers. Fish exposed to high CO2 typically experience a reduction in blood and tissue pH, however, there are limits to extracellular (blood) pH regulation at CO2 levels beyond 3 - 4 kPa which may also limit tissue pH compensation leading to difficulties surviving these conditions. Fish living in these high CO2 environments were hypothesized to use a different strategy of pH regulation termed "preferential intracellular pH regulation" which prevents any reduction in tissue pH despite sustained reduction in blood pH. I investigated if preferential intracellular pH regulation is common and widespread strategy of pH regulation amongst fish. 
Key publications:
  • Shartau RB, Baker DW, Harter TS, Aboagye DL, Allen PJ, Val AL, Crossley II DA, Kohl ZF, Hedrick MS, Damsgaard D and Brauner CJ. 2020. Preferential intracellular pH regulation is a common trait amongst fish exposed to high CO2. Journal of Experimental Biology. 223: jeb208868 doi: 10.1242/jeb.208868.
  • Shartau RB, Damsgaard C and Brauner CJ. 2019. Limits and patterns of acid-base regulation during elevated environmental CO2 in fish. (Invited review). Comparative Biochemistry and Physiology A. 236: 110524.
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Developmental change in acid-base regulation

Some animals, such as reptiles, experience high CO2 during development as nest CO2 levels can reach 6 kPa (~60,000 uatm). I investigated how two reptile species (American alligator and common snapping turtles) regulate extracellular and tissue pH during high CO2 exposure at different developmental stages ranging from 70% to hatch, to yearlings.
Key publications:
  • Shartau RB, Crossley II DA, Kohl ZF, Elsey RM and Brauner CJ. 2018. American alligator (Alligator mississippiensis) embryos tightly regulate intracellular pH during a severe acidosis. Canadian Journal of Zoology. 96(7): 723-727.
  • Shartau RB, Crossley II DA, Kohl ZF and Brauner CJ. 2016. Embryonic common snapping turtles (Chelydra serpentina) preferentially regulate tissue pH during acid-base challenges. Journal of Experimental Biology. 219(13): 1994-2002.
  • ​Shartau RB, Baker DW, Crossley II DA and Brauner CJ. 2016. Preferential intracellular pH regulation: hypotheses and perspectives. (Invited commentary). Journal of Experimental Biology. 219(15): 2235- 2244.
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Algal toxins and salmon physiology

Harmful algal blooms release toxins into the aquatic environment affecting animals. Toxins associated with blue-green algae (cyanobacteria) are believed to be associated with net pen liver disease (NPLD), a serious disease of salmon that is hypothesized to arise from exposure to microcystins, a cyanobacterial toxin that is commonly associated with freshwater environments and some marine environments. Incidences of toxic cyanobacterial blooms are increasing due to climate change, eutrophication, and other anthropogenic driven factors. I investigated the presence of microcystin and other algal toxins on the southern coast of British Columbia Canada. I also investigated the effect of sub-lethal microcystin exposure on Atlantic and Chinook salmon by examining histopathology, metabolites, and gene expression.
Key publication:
  • Shartau RB, Heindrich SN, Turcotte L, McCarron P, Bradshaw JC and Johnson SC. 2022. Acute microcystin exposure induces reversible histopathological changes in Chinook Salmon (Oncorhynchus tshawytscha) and Atlantic Salmon (Salmo salar). Journal of Fish Diseases. DOI: 10.1111/jfd.13599.
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Severe net-pen liver disease in Atlantic Salmon

Sturgeon physiology

White sturgeon (Acipenser transmontanus) is the largest freshwater fish species in North America and are believed to have existed as a species for over 46 million years, with sturgeon as a group originating roughly 200 million years ago. Due to their 'primitive' origins and threatened conservation status, they represent an excellent model to investigate physiology questions to provide insight into the evolution of fishes and improve our understanding of the physiological responses to natural and human-driven environmental changes. In collaboration with Dr. Dan Baker, we are investigating how salinity acclimation and water chemistry affects acid-base and ion regulation.
Key publication:
  • Shartau RB, Shu J, Baker DW. The role of salinity in recovery of white sturgeon (Acipenser transmontanus) from stimulated angling stress. Conservation Physiology. Accepted (manuscript number: CONPHYS-2022-083).
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