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Consequences of high temperatures and premature mortality on the transcriptome and blood physiology of wild adult sockeye salmon (Oncorhynchus nerka)


Jeffries, KM and Hinch, SG and Sierocinski, T and Clark, TD and Eliason, EJ and Donaldson, MR and Li, S and Pavlidis, P and Miller, KM, Consequences of high temperatures and premature mortality on the transcriptome and blood physiology of wild adult sockeye salmon (Oncorhynchus nerka), Ecology and Evolution, 2, (7) pp. 1747-1764. ISSN 2045-7758 (2012) [Refereed Article]

DOI: doi:10.1002/ece3.274


Elevated river water temperature in the Fraser River, British Columbia, Canada, has been associated with enhanced mortality of adult sockeye salmon (Oncorhynchus nerka) during their upriver migration to spawning grounds. We undertook a study to assess the effects of elevated water temperatures on the gill transcriptome and blood plasma variables in wild-caught sockeye salmon. Naturally migrating sockeye salmon returning to the Fraser River were collected and held at ecologically relevant temperatures of 14C and 19C for seven days, a period representing a significant portion of their upstream migration. After seven days, sockeye salmon held at 19C stimulated heat shock response genes as well as many genes associated with an immune response when compared with fish held at 14C. Additionally, fish at 19C had elevated plasma chloride and lactate, suggestive of a disturbance in osmoregulatory homeostasis and a stress response detectable in the blood plasma. Fish that died prematurely over the course of the holding study were compared with time-matched surviving fish; the former fish were characterized by an upregulation of several transcription factors associated with apoptosis and downregulation of genes involved in immune function and antioxidant activity. Ornithine decarboxylase (ODC1) was the most significantly upregulated gene in dying salmon, which suggests an association with cellular apoptosis. We hypothesize that the observed decrease in plasma ions and increases in plasma cortisol that occur in dying fish may be linked to the increase in ODC1. By highlighting these underlying physiological mechanisms, this study enhances our understanding of the processes involved in premature mortality and temperature stress in Pacific salmon during migration to spawning grounds.

Item Details

Item Type:Refereed Article
Keywords:ecological genomics, Pacific salmon, premature mortality, spawning migration, stress, temperature
Research Division:Biological Sciences
Research Group:Zoology
Research Field:Animal behaviour
Objective Division:Environmental Management
Objective Group:Coastal and estuarine systems and management
Objective Field:Coastal or estuarine biodiversity
UTAS Author:Clark, TD (Dr Timothy Clark)
ID Code:103379
Year Published:2012
Web of Science® Times Cited:67
Deposited By:IMAS Research and Education Centre
Deposited On:2015-10-07
Last Modified:2017-10-31

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