Effect of Short-Duration Seawater Exposure on Plasma Ion Concentrations and Swimming Performance in Coho Salmon (Oncorhynchus kisutch) Parr

1992 ◽  
Vol 49 (11) ◽  
pp. 2399-2405 ◽  
Author(s):  
C. J. Brauner ◽  
J. M. Shrimpton ◽  
D. J. Randall

The effect of seawater (sw) on plasma ion concentrations and critical swimming velocity (Ucrit) was investigated in hatchery-reared coho salmon (Oncorhynchus kisutch) parr exposed to one of four treatments: 24 h of seawater exposure (SW1), 5–7 d of seawater (SW5), 24 h in seawater followed by 24 h in fresh water (SW-FW), and a freshwater control (FWC). Only the SW1 fish demonstrated a reduced Ucrit and, at rest, elevated plasma [Na+], [Cl−], and [SO42−]. With exercise, SW1 fish were characterized by an increase in plasma ion concentrations and a decrease in both hematocrit (Hct) and muscle moisture content. There is a strong relationship between plasma [Na+] at rest and Ucrit, where an optimal swimming velocity is obtained in animals with resting levels of approximately 147 mEq∙L−1. Traditionally, the 24-h seawater challenge is used to test the hypoosmoregulatory ability in smolting salmonids, however, our data suggest that it may also predict the aerobic swimming potential of salmonids following seawater transfer. We suggest that the reduction in Hct and increase in plasma [Na+] result in reduced oxygen delivery to the muscle and that decrease in muscle moisture content impairs the contractile process.

1994 ◽  
Vol 51 (10) ◽  
pp. 2188-2194 ◽  
Author(s):  
C. J. Brauner ◽  
G. K. Iwama ◽  
D. J. Randall

The critical swimming velocity (Ucrit) and haematology of wild and hatchery-reared coho salmon (Oncorhynchus kisutch) juveniles were examined in either fresh water or seawater following a 24-h seawater challenge, at the time of smoltification. In fresh water, wild smolts swam faster than hatchery-reared fish but this could largely be accounted for by scaling for body size. Transfer to seawater significantly elevated resting plasma [Na+] and reduced subsequent Ucrit in hatchery fish (by 12%) relative to that determined in fresh water but had no significant effect on resting plasma [Na+] and Ucrit in wild fish. Swimming the fish a second time in seawater after the initial 2-h exercise period resulted in a significant reduction in Ucrit relative to that in fresh water in both wild fish (16%) and hatchery fish (a further 14%); this relatively greater impairment in Ucrit in hatchery fish was due to a reduced hypo-osmoregulatory ability following seawater transfer that impairs conditions for muscle contractility and aerobic metabolism. Aerobic metabolism in seawater-exposed fish was affected in part through a reduction in haematocrit and an increase in plasma volume, reducing oxygen carrying capacity of the blood relative to conditions in fresh water.


1988 ◽  
Vol 45 (8) ◽  
pp. 1487-1490 ◽  
Author(s):  
Scott W. Johnson ◽  
Jonathan Heifetz

Osmoregulatory ability of wild coho salmon (Oncorhynchus kisutch) and Dolly Varden char (Salvelinus malma) smolts migrating from a small stream in southeastern Alaska was assessed by plasma Na+ levels after a 24-h seawater challenge. Osmoregulatory ability of coho salmon was unaffected by time of out-migration, water temperature, and fish size. Osmoregulatory ability of Dolly Varden char was apparently affected by time of out-migration or water temperature but not by fish size. Char migrating in the first half of the migration period, when water temperature was usually < 8.0 °C, had lower plasma Na+ levels than did char migrating in the second half when temperatures were [Formula: see text]. A plasma Na+ threshold of 170 mmol∙L−1, used by others to separate smolts from silvery parr, indicated that 70% of the coho salmon and 80% of the Dolly Varden char we sampled were physiologically prepared to enter seawater. The remaining fish may have suffered some level of osmoregulatory stress.


1989 ◽  
Vol 46 (2) ◽  
pp. 243-245 ◽  
Author(s):  
Susan A. Small ◽  
D. J. Randall

The swimming performance of triploid coho salmon (Oncorhynchus kisutch) was compared with diploid controls to assess the ability of these fish to survive if released into the wild. Triploid salmon had similar haematocrits to diploid salmon but they had lower total haemoglobin content in their blood. There was no difference in the maximum sustained swimming ability between triploid and diploid salmon.


1997 ◽  
Vol 75 (2) ◽  
pp. 335-337 ◽  
Author(s):  
Anthony P. Farrell ◽  
William Bennett ◽  
Robert H. Devlin

We examined the consequence of remarkably fast growth rates in transgenic fish, using swimming performance as a physiological fitness variable. Substantially faster growth rates were achieved by the insertion of an "all-salmon" growth hormone gene construct in transgenic coho salmon (Oncorhynchus kisutch). On an absolute speed basis, transgenic fish swam no faster at their critical swimming speed than smaller non-transgenic controls, and much slower than older non-transgenic controls of the same size. Thus, we find a marked trade-off between growth rate and swimming performance, and these results suggest that transgenic fish may be an excellent model to evaluate existing ideas regarding physiological design.


1975 ◽  
Vol 32 (6) ◽  
pp. 789-793 ◽  
Author(s):  
T. E. Howard

Maximum critical swimming speeds were not achieved by fingerling coho salmon (Oncorhynchus kisutch) in concentrations of bleached kraft pulpmill effluent above a threshold concentration between 10–20% of the 96-h LC50. Reduction of swimming performance was related to effluent concentration but not to exposure time after the initial 18 h. Swimming performance returned to control levels for fish tested in water after 6–12 h recovery from exposure to effluent concentrations up to 0.7 LC50. Effluent was rendered nontoxic by aerobic microbiological fermentation but some reduction in swimming performance was measured which was attributed, in part, to the effects of color and lignin materials remaining after treatment.The results are discussed in relation to the mode of toxic action of bleached kraft pulpmill effluents and their possible impact on aquatic ecosystems.


2020 ◽  
Vol 9 (1) ◽  
Author(s):  
K Kraskura ◽  
E A Hardison ◽  
A G Little ◽  
T Dressler ◽  
T S Prystay ◽  
...  

Abstract Adult female Pacific salmon can have higher migration mortality rates than males, particularly at warm temperatures. However, the mechanisms underlying this phenomenon remain a mystery. Given the importance of swimming energetics on fitness, we measured critical swim speed, swimming metabolism, cost of transport, aerobic scope (absolute and factorial) and exercise recovery in adult female and male coho salmon (Oncorhynchus kisutch) held for 2 days at 3 environmentally relevant temperatures (9°C, 14°C, 18°C) in fresh water. Critical swimming performance (Ucrit) was equivalent between sexes and maximal at 14°C. Absolute aerobic scope was sex- and temperature-independent, whereas factorial aerobic scope decreased with increasing temperature in both sexes. The full cost of recovery from exhaustive exercise (excess post-exercise oxygen consumption) was higher in males compared to females. Immediately following exhaustive exercise (i.e. 1 h), recovery was impaired at 18°C for both sexes. At an intermediate time scale (i.e. 5 h), recovery in males was compromised at 14°C and 18°C compared to females. Overall, swimming, aerobic metabolism, and recovery energetics do not appear to explain the phenomenon of increased mortality rates in female coho salmon. However, our results suggest that warming temperatures compromise recovery following exhaustive exercise in both male and female salmon, which may delay migration progression and could contribute to en route mortality.


1992 ◽  
Vol 171 (1) ◽  
pp. 301-314 ◽  
Author(s):  
P. GALLAUGHER ◽  
M. AXELSSON ◽  
A. P. FARRELL ◽  
A.P. FARRELL

Haematological variables were measured during aerobic swimming (45–55% of Ucrit) and at critical swimming velocity (Ucrit) in acutely splenectomized and sham-operated rainbow trout. There was no correlation between haematocrit (Hct) and Ucrit in either group of fish. The control values for the haematological variables did not differ significantly between the two groups of fish. Some haematological variables changed during aerobic swimming and at Ucrit, but there were no significant differences between the two groups for any of the variables. Arterial blood oxygen tension was significantly reduced at Ucrit. Arterial blood oxygen content (CaOO2) was maintained in sham-operated fish because the Hct increased significantly. However, in the splenectomized animals, CaOO2 decreased (compared to control values) during aerobic swimming and at Ucrit because the Hct did not change. Plasma concentrations of lactate and catecholamines were elevated only at Ucrit. We provide evidence of a graded spleen contraction during aerobic swimming.


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