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Sex-specific differences in cardiac control and hematology of sockeye salmon (Oncorhynchus nerka) approaching their spawning grounds

Citation

Sandblom, E and Clark, TD and Hinch, SG and Farrell, AP, Sex-specific differences in cardiac control and hematology of sockeye salmon (Oncorhynchus nerka) approaching their spawning grounds, American Journal of Physiology, 297, (4) pp. R1136-R1143. ISSN 0363-6119 (2009) [Refereed Article]

DOI: doi:10.1152/ajpregu.00363.2009

Abstract

Some male salmonids (e.g., rainbow trout) display profound cardiovascular adjustments during sexual maturation, including cardiac growth and hypertension, and tachycardia has been observed in free-ranging male salmonids near their spawning grounds. In the present study, we investigated cardiac control, dorsal aortic blood pressure, cardiac morphometrics, and hematological variables in wild, sexually maturing sockeye salmon (Oncorhynchus nerka) with a particular aim to decipher any sex-specific differences. Routine heart rate (fH) was significantly higher in females (52 vs. 43 beats/min), which was due to significantly lower cholinergic tone (28 vs. 46%), because there were no differences in adrenergic tone or intrinsic heart rate between sexes. No differences in blood pressure were observed despite males possessing an 11% greater relative ventricular mass. Concomitant with higher routine heart rates, female sockeye had significantly higher levels of cortisol, testosterone, and 17β-estradiol, whereas the level of 11-ketotestosterone was higher in males. There were no differences in hematocrit or hemoglobin concentration between the sexes. The findings of this study highlight the importance of considering sex as a variable in research fields such as conservation biology and when modeling the consequences of local and global climate change. Indeed, this study helps to provide a mechanistic basis for the significantly higher rates of female mortality observed in previous studies of wild-caught sockeye salmon.

Item Details

Item Type:Refereed Article
Keywords:blood pressure, cardiac sympathovagal tone, hemoglobin, hematocrit, sex hormones
Research Division:Biological Sciences
Research Group:Zoology
Research Field:Animal Behaviour
Objective Division:Environment
Objective Group:Flora, Fauna and Biodiversity
Objective Field:Coastal and Estuarine Flora, Fauna and Biodiversity
UTAS Author:Clark, TD (Dr Timothy Clark)
ID Code:103417
Year Published:2009
Web of Science® Times Cited:38
Deposited By:IMAS Research and Education Centre
Deposited On:2015-10-08
Last Modified:2015-10-08
Downloads:0

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