| 1. |
- Clark, T.D., et al.
(author)
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Calibration of a hand-held haemoglobin analyser for use on fish blood
- 2008
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In: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 73:10, s. 2587-2595
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Journal article (peer-reviewed)abstract
- The HemoCue haemoglobin analyser consistently overestimated haemoglobin concentration ([Hb]) in the blood of all fish species (sockeye salmon Oncorhynchus nerka, Chinook salmon Oncorhynchus tshawytscha, Pacific bluefin tuna Thunnus orientalis and chub mackerel Scomber japonicus) by 22–50% (9·9–36·0 g l−1) over a [Hb] range of 20–160 g l−1. The systematic nature of the overestimation, however, allowed the formulation of an accurate calibration equation that can be used to correct values of [Hb] measured by the HemoCue in field studies.
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| 2. |
- Clark, T.D., et al.
(author)
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Circulatory limits to oxygen supply during an acute temperature increase in the Chinook salmon (Oncorhynchus tshawytscha)
- 2008
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In: American Journal of Physiology: Regulatory, Integrative and Comparative Physiology. - : American Physiological Society. - 0363-6119 .- 1522-1490. ; 295
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Journal article (peer-reviewed)abstract
- This study was undertaken to provide a comprehensive set of data relevant to disclosing the physiological effects and possible oxygen transport limitations in the Chinook salmon (Oncorhynchus tshawytscha) during an acute temperature change. Fish were instrumented with a blood flow probe around the ventral aorta and catheters in the dorsal aorta and sinus venosus. Water temperature was progressively increased from 13°C in steps of 4°C up to 25°C. Cardiac output increased from 29 to 56 ml·min–1·kg–1 between 13 and 25°C through an increase in heart rate (58 to 105 beats/min). Systemic vascular resistance was reduced, causing a stable dorsal aortic blood pressure, yet central venous blood pressure increased significantly at 25°C. Oxygen consumption rate increased from 3.4 to 8.7 mg·min–1·kg–1 during the temperature increase, although there were signs of anaerobic respiration at 25°C in the form of increased blood lactate and decreased pH. Arterial oxygen partial pressure was maintained during the heat stress, although venous oxygen partial pressure (PvO2) and venous oxygen content were significantly reduced. Cardiac arrhythmias were prominent in three of the largest fish (>4 kg) at 25°C. Given the switch to anaerobic metabolism and the observation of cardiac arrhythmias at 25°C, we propose that the cascade of venous oxygen depletion results in a threshold value for PvO2 of around 1 kPa. At this point, the oxygen supply to systemic and cardiac tissues is compromised, such that the oxygen-deprived and acidotic myocardium becomes arrhythmic, and blood perfusion through the gills and to the tissues becomes compromised.
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| 3. |
- Cooke, S.J., et al.
(author)
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Developing a mechanistic understanding of fish migrations by linking telemetry with physiology, behavior, genomics and experimental biology: an interdisciplinary case study on adult fraser river sockeys salmon
- 2008
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In: Fisheries. ; 33:7, s. 321-338
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Journal article (peer-reviewed)abstract
- Fish migration represents one of the most complex and intriguing biological phenomena in the animal kingdom. How do fish migrate such vast distances? What are the costs and benefits of migration? Some of these fundamental questions have been addressed through the use of telemetry. However, telemetry alone has not and will not yield a complete understanding of the migration biology of fish or provide solutions to problems such as identifying physical barriers to migration or understanding potential impacts of climate change. Telemetry can be coupled with other tools and techniques to yield new insights into animal biology. Using Fraser River sockeye salmon (Oncorhynchus nerka) as a model, we summarize the advances that we have made in understanding salmonid migration biology through the integration of disciplines (i.e., interdisciplinary research) including physiology, behavior, functional genomics, and experimental biology. We also discuss opportunities for using large-scale telemetry arrays and taking a more experimental approach to studies of fish migration that use telemetry (i.e., intervention studies involving endocrine implants, simulated migration studies) rather than simply focusing on descriptive or correlational techniques. Only through integrative and interdisciplinary research will it be possible to understand the mechanistic basis of fish migrations and to predict and possibly mitigate the consequences of anthropogenic impacts. Telemetry is a tool that has the potential to integrate research across disciplines and between the lab and the field to advance the science of fish migration biology. The techniques that we have applied to the study of Pacific salmon are equally relevant to other fish taxa in both marine and freshwater systems as well as migratory animals beyond ichthyofauna. The interdisciplinary approach used here was essential to address a pressing and complex conservation problem association with sockeye salmon migration.
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| 4. |
- Sandblom, Erik, 1978, et al.
(author)
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Sex-specific differences in cardiovascular physiology of Sockeye salmon (Oncorhynchus nerka) approaching their spawning grounds
- 2009
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In: American Journal of Physiology: Regulatory, Integrative and Comparative Physiology. ; 297
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Journal article (peer-reviewed)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.
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| 5. |
- Van Wert, J. C., et al.
(author)
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Population variability in thermal performance of pre-spawning adult Chinook salmon
- 2023
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In: Conservation Physiology. - 2051-1434. ; 11:1
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Journal article (peer-reviewed)abstract
- Climate change is causing large declines in many Pacific salmon populations. In particular, warm rivers are associated with high levels of premature mortality in migrating adults. The Fraser River watershed in British Columbia, Canada, supports some of the largest Chinook salmon (Oncorhynchus tshawytscha) runs in the world. However, the Fraser River is warming at a rate that threatens these populations at critical freshwater life stages. A growing body of literature suggests salmonids are locally adapted to their thermal migratory experience, and thus, population-specific thermal performance information can aid in management decisions. We compared the thermal performance of pre-spawning adult Chinook salmon from two populations, a coastal fall-run from the Chilliwack River (125 km cooler migration) and an interior summer-run from the Shuswap River (565 km warmer migration). We acutely exposed fish to temperatures reflecting current (12 degrees C, 18 degrees C) and future projected temperatures (21 degrees C, 24 degrees C) in the Fraser River and assessed survival, aerobic capacity (resting and maximum metabolic rates, absolute aerobic scope (AAS), muscle and ventricle citrate synthase), anaerobic capacity (muscle and ventricle lactate dehydrogenase) and recovery capacity (post-exercise metabolism, blood physiology, tissue lactate). Chilliwack Chinook salmon performed worse at high temperatures, indicated by elevated mortality, reduced breadth in AAS, enhanced plasma lactate and potassium levels and elevated tissue lactate concentrations compared with Shuswap Chinook salmon. At water temperatures exceeding the upper pejus temperatures (T-pejus, defined here as 80% of maximum AAS) of Chilliwack (18.7 degrees C) and Shuswap (20.2 degrees C) Chinook salmon populations, physiological performance will decline and affect migration and survival to spawn. Our results reveal population differences in pre-spawning Chinook salmon performance across scales of biological organization at ecologically relevant temperatures. Given the rapid warming of rivers, we show that it is critical to consider the intra-specific variation in thermal physiology to assist in the conservation and management of Pacific salmon. Warming water temperatures threaten aquatic species and impact economies and cultures. Yet, vulnerability can vary within a species. We assessed the thermal performance of two populations of pre-spawning adult Chinook salmon and found that an interior summer-run population of Chinook salmon performed better at warmer temperatures than a coastal fall-run population. Current river temperatures already exceed the functional warming tolerances of both populations and highlight the value of physiological studies in supporting management decisions.
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