Physiological Responses to Challenge Tests in Six Stocks of Coho Salmon (Oncorhynchus kisutch)

1991 ◽  
Vol 48 (9) ◽  
pp. 1761-1771 ◽  
Author(s):  
James C. McGeer ◽  
Leanne Baranyi ◽  
George K. Iwama
Keyword(s):  
Plasma Glucose ◽  
Thermal Tolerance ◽  
Coho Salmon ◽  
Salt Water ◽  
Oncorhynchus Kisutch ◽  
Chloride Ion ◽  
Tolerance Test ◽  
Plasma Sodium ◽  
High Ph ◽  
Challenge Tests

Coho salmon (Oncorhynchus kisutch) from six hatcheries were reared in a common facility and then subjected to six different challenge tests. Results indicated that there are differences in the response to stressful challenges among stocks of coho salmon. The challenge tests were exposure to salt water (30‰), high pH (9.4 and 10.0), low pH (3.55, 3.65, 3.75, and 4.1), thermal increase (1°C∙h−1), disease (bacterial kidney disease), and handling (30-s netting and emersion). The measured responses were changes in plasma sodium and chloride ion concentrations for the saline and pH challenges, critical thermal maximum in the thermal tolerance test, mortalities in the disease challenge, and plasma glucose alterations in the handling challenge. The Chehalis River stock was most successful in tolerating salt water but showed the largest plasma ion decrease in acidic waters. The stock from Eagle River had the lowest plasma glucose increase during handling challenges. In the disease challenge the Tenderfoot Creek and Eagle River stocks had high mortalities but the Capilano River stock had the lowest mortality. No stock differences were found during thermal tolerance and high pH challenges. An assessment of overall stock performance across challenges showed that each stock had a unique response profile.

Differences in Measurements of Smolt Development Between Wild and Hatchery-Reared Juvenile Coho Salmon (Oncorhynchus kisutch) Before and After Saltwater Exposure

1994 ◽  
Vol 51 (10) ◽  
pp. 2170-2178 ◽  
Author(s):  
J. Mark Shrimpton ◽  
Nicholas J. Bernier ◽  
George K. Iwama ◽  
David J. Randall
Keyword(s):  
Citrate Synthase ◽  
Coho Salmon ◽  
Sea Water ◽  
Salt Water ◽  
Oncorhynchus Kisutch ◽  
Sodium Concentration ◽  
Chloride Cells ◽  
Plasma Sodium ◽  
Hatchery Fish ◽  
Saltwater Tolerance

We compared the saltwater tolerance of coho salmon (Oncorhynchus kisutch) juveniles that were reared in different environments. The groups examined consisted of fish reared exclusively in the hatchery, a hatchery group transplanted into the upper watershed of the river (colonized), and wild fish from natural spawning broodstock in the river. Although hatchery fish were much larger than their wild or colonized counterparts, they consistently showed a reduced saltwater tolerance as assessed by a much greater perturbation in plasma sodium concentration following transfer to salt water. Within each group there was no relationship between size of the fish and saltwater tolerance. Following transfer to sea water, hatchery fish showed a significant decline in haematocrit and a significant increase in circulating plasma cortisol concentration. Neither of these changes was seen in wild smolts. Hatchery fish possessed fewer chloride cells, and lower specific activities of the enzymes Na+K+ATPase and citrate synthase. The weaker osmoregulatory ability of hatchery fish led to a greater mortality following abrupt transfer to 35‰ seawater. We believe that the differences in saltwater tolerance seen among the different groups of fish are due to rearing environment.

Stress Response of Coho Salmon (Oncorhynchus kisutch) Elicited by Cadmium and Copper and Potential Use of Cortisol as an Indicator of Stress

1978 ◽  
Vol 35 (8) ◽  
pp. 1124-1129 ◽  
Author(s):  
Carl B. Schreck ◽  
Harold W. Lorz
Keyword(s):  
Coho Salmon ◽  
Salt Water ◽  
Oncorhynchus Kisutch ◽  
Serum Cortisol ◽  
Stress Indicator ◽  
Water Handling ◽  
Serum Chloride ◽  
General Adaptation ◽  
Dose Dependent ◽  
Potential Use

Exposure of juvenile coho salmon (Oncorhynchus kisutch) to copper (Cu) produced a marked, dose-dependent serum cortisol elevation. Treatment with cadmium (Cd) did not elicit a cortisol elevation, even in moribund fish. Stressing salmon with sublethal levels of Cu or handling plus close confinement resulted in "ideal" compensation (return to prestress levels) in cortisol titers. Salmon exposed to Cu had depressed serum chloride levels and reduced survival when challenged with salt water. Exposure to Cd did not influence serum chloride or the ability to tolerate salt water. Handling and close confinement produced the same cortisol elevation in controls as in Cu- or Cd-treated fish, but exposure to Cu reduced the ability of the fish to survive the stress of handling and confinement. Cortisol level and other characteristics of the General Adaptation Syndrome of stress should not be universally applied as indicators of stress in salmon. Key words: stress, cortisol, heavy metals, coho salmon, Oncorhynchus kisutch, saltwater adaptation, stress resistance, stress indicator, cadmium, copper

Influence of salinity on ultrastructure of the secretory cells of the adenohypophyseal pars distalis in yearling coho salmon (Oncorhynchus kisutch)

1977 ◽  
Vol 55 (1) ◽  
pp. 183-198 ◽  
Author(s):  
Yoshitaka Nagahama ◽  
W. Craig Clarke ◽  
W. S. Hoar
Keyword(s):  
Freshwater Fish ◽  
Fresh Water ◽  
Coho Salmon ◽  
Sea Water ◽  
Salt Water ◽  
Light And Electron Microscopy ◽  
Secretory Cells ◽  
Plasma Sodium ◽  
Pars Distalis ◽  
Freshwater Environment

Six different types of secretory cells were identified by light and electron microscopy in the adenohypophyseal pars distalis of yearling coho salmon acclimated to fresh or salt water. Prolactin cells are markedly more active in the freshwater than the seawater fish; these cells exhibit definite functional activity 3 days after transfer from salt to fresh water, indicating an osmoregulatory role of prolactin in the freshwater environment. Plasma sodium showed a significant decline 6 h after transfer from sea water to fresh water and, even after 1 week, remained lower than in the fully acclimated freshwater fish. Corticotropic (ACTH) cells did not appear cytologically different in freshwater and seawater fish. GH cells, the most prominent cells in the proximal pars distalis, appear more numerous and more granulated in the seawater fish, suggesting an osmoregulatory involvement in young coho salmon. Putative thyrotropic (TSH) and putative gonadotropic cells (GTH) can be distinguished by differences in granulation; only one type of GTH cell is evident with ultrastructural features that differ from those of sexually mature salmon. Stellate, non-granulated cells occur in all regions of the adenohypophysis but more frequently in the prolactin follicles; they are much more prominent in the seawater than freshwater fish.

Stunting of Wild Coho Salmon (Oncorhynchus kisutch) in Seawater: Patterns of Plasma Thyroid Hormones, Cortisol, and Growth Hormone

1992 ◽  
Vol 49 (3) ◽  
pp. 458-461 ◽  
Author(s):  
Vladimir S. Varnavsky ◽  
Tatsuya Sakamoto ◽  
Tetsuya Hirano
Keyword(s):  
Growth Hormone ◽  
Thyroid Hormones ◽  
Brackish Water ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
River Mouth ◽  
High Growth ◽  
Sodium Concentration ◽  
Plasma Sodium ◽  
Plasma Sodium Concentration

Under natural conditions, some coho salmon presmolts (Oncorhynchus kisutch) in Kamchatka have been observed to migrate prematurely to the sea and fail to grow in brackish water for prolonged periods (natural stunts). Plasma levels of growth hormone, cortisol, thyroxine, and triiodothyronine were measured in coho salmon parr captured in the river (freshwater), smolts migrating downstream captured at the river mouth (brackish water), smolts in the sea (seawater), and natural stunts in the inlet (brackish water). The physiological conditions of natural stunts seem analogous to those of hatchery-derived stunts observed in hatchery-reared juveniles in sea pens, with normal plasma sodium concentration, low levels of thyroid hormones and cortisol, and high growth hormone levels.

Protective Effect of Chloride on Nitrite Toxicity to Coho Salmon (Oncorhynchus kisutch)

1977 ◽  
Vol 34 (4) ◽  
pp. 486-492 ◽  
Author(s):  
Stephen J. Perrone ◽  
Thomas L. Meade
Keyword(s):  
Protective Effect ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Chloride Ion ◽  
Nitrite Nitrogen ◽  
Nitrite Toxicity ◽  
Flow Through

Tolerance of coho salmon (Oncorhynchus kisutch) to nitrite was increased when the concentration of chloride ion in the environment was high. The results of flow-through bioassays revealed that no mortality occurred when yearling coho salmon were subjected to nitrite-nitrogen (NO2−–N) of 29.8 mg/ℓ and chloride (Cl−) of 261.3 mg/ℓ for 48 h. When yearling coho salmon were exposed to 3.8 mg/ℓ NO2−–N and 2.5 mg/ℓ Cl− for 12 h, the resultant mortality was 58.3%. Possibly, chloride competes with nitrite for transport across the gills and integumental tissues, thereby interfering with the onset of nitrite-induced methemoglobinemia.

Effects of Acclimation and Acute Temperature Experience on the Swimming Speed of Juvenile Coho Salmon

1972 ◽  
Vol 29 (3) ◽  
pp. 251-264 ◽  
Author(s):  
J. S. Griffiths ◽  
D. F. Alderdice
Keyword(s):  
Thermal Tolerance ◽  
Performance Test ◽  
Coho Salmon ◽  
Swimming Performance ◽  
Oncorhynchus Kisutch ◽  
Winter Period ◽  
Acclimation Temperature ◽  
Temperature Level ◽  
Maximum Performance ◽  
Apparent Shift

Swimming performance of juvenile coho salmon (Oncorhynchus kisutch), 7.5–9.5 cm in total length, was investigated in a stamina tunnel, generally at 3 C intervals of temperature over the range of thermal tolerance.Optimum (ultimate maximum) performance (5.8 lengths/sec) occurred at a combination of acclimation and test temperatures near 20 C. A declining ridge of sub-optimum performance (test temperature ridge) was found at acclimation temperatures below 20 C; maximum performance at each acclimation temperature level was found on the ridge at test temperatures higher than those of acclimation. Conversely, maximum performance at given test temperatures occurred on a second ridge (acclimation temperature ridge) at acclimation temperatures near those of testing. There was an apparent shift in location of the acclimation temperature ridge, indicative of seasonal performance compensation and improved capacity to perform at low acclimation temperatures during the winter period. At test temperatures below 5 C, maximum performance occurred at acclimation temperatures of about 6–8 C. Lowest performance within the zone of thermal tolerance was associated with acclimation and test temperatures of 2 C.

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