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.

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.

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.

Studies on Salt and Water Balance in Caddis Larvae (Trichoptera)

1961 ◽  
Vol 38 (3) ◽  
pp. 521-530 ◽  
Author(s):  
D. W. SUTCLIFFE
Keyword(s):  
Sea Water ◽  
Salt Water ◽  
Chloride Concentration ◽  
Malpighian Tubule ◽  
Sodium Concentration ◽  
Fluid Composition ◽  
Chloride Level ◽  
Highly Sensitive ◽  
Water Media ◽  
Salt And Water Balance

1. Survival and regulation in sea-water media was studied in the freshwater caddises Limnephilus stigma and Anabolia nervosa. 2. The majority of larvae did not survive for more than a few days at external salt concentrations greater than about 6o mM./l. NaCl. 3. In sea-water media the haemolymph osmotic pressure increased to remain slightly hyper-osmotic to the medium. The haemolymph sodium level also increased to remain slightly hypertonic to the medium, but the chloride level was maintained hypotonic until just prior to death of the larvae. 4. When the haemolymph chloride concentration was raised above the normal level, the Malpighian tubule-rectal system elaborated fluid in which the chloride concentration was hypertonic to the haemolymph. The system is highly sensitive to changes in the haemolymph chloride level. 5. The regulation of body-fluid composition in the freshwater caddises is compared with that found previously in the euryhaline larvae of Limnephilus affinis. It is suggested that the maintenance of a low haemolymph sodium concentration in L. affinis larvae is an important part of the adaptation for survival in salt water.

CO2 and H+ Excretion by Swimming Coho Salmon, Oncorhynchus Kisutch

1983 ◽  
Vol 107 (1) ◽  
pp. 169-180
Author(s):  
GUIDO VAN DEN THILLART ◽  
DAVID RANDALL ◽  
LIN HOA-REN
Keyword(s):  
High Speed ◽  
Coho Salmon ◽  
Sea Water ◽  
Oncorhynchus Kisutch ◽  
Hydrogen Ion ◽  
Ion Transfer ◽  
Bicarbonate Concentration ◽  
Seawater Ph ◽  
External Conditions ◽  
Co2 Excretion

Coho salmon, Oncorhynchus kisutch (Walbaum), were swum at constant speed in a ‘Brett-type’ tunnel respirometer. Blood PO2, PCO2 and pH as well as total CO2 content and red blood cell pH were unchanged during swimming. The RE (respiratory exchange ratio) was slightly less than 0.7 when the fish was swimming in normal sea water, indicating that some CO2 retained by the fish. Lowering seawater bicarbonate concentration increased HCO3− transfer, presumably because of passive bicarbonate loss. A reduction in seawater pH from 7.95 to 7.1 sharply reduced both CO2 and hydrogen ion transfer, resulting in very low RE values of about 0.2. Hydrogen ion excretion was elevated during prolonged swimming following high speed swimming activity. It would appear that CO2 and hydrogen ion transfer by fish need not be matched and changing internal and external conditions can have a marked and separate effect on hydrogen ion and CO2 excretion and therefore on the RE value.

Effects of Early Rearing Environment on Stress Response, Immune Function, and Disease Resistance in Juvenile Coho (Oncorhynchus kisutch) and Chinook Salmon (O.tshawytscha)

1993 ◽  
Vol 50 (4) ◽  
pp. 759-766 ◽  
Author(s):  
Kira Salonius ◽  
George K. Iwama
Keyword(s):  
Disease Resistance ◽  
Chinook Salmon ◽  
Coho Salmon ◽  
Vibrio Anguillarum ◽  
Oncorhynchus Kisutch ◽  
Significant Rise ◽  
Wild Fish ◽  
Handling Stress ◽  
Hatchery Fish ◽  
Natural Water Body

Coho (Oncorhynchus kisutch) and chinook salmon (0. tshawytscha) from aquaculture and wild environments were subjected to handling (30–60 s of netting and aerial emersion) and disease challenges. Plasma cortisol concentrations ([cortisol]pl) in both coho and chinook salmon from wild environments were significantly elevated 4 h after handling. Colonized coho salmon (hatchery-reared fish, transported into a natural water body as fry) responded in a similar fashion to wild fish, while those reared entirely in the hatchery showed no significant rise in [cortisol]pl. The responses to handling stress were retained in wild and colonized coho salmon after 7 mo of hatchery rearing. A transient increase in the leukocyte to red blood cell ratio in both wild and hatchery-reared chinook salmon occurred 4 h after handling. Handling signficantly decreased the antibody-producing cell (APC) number in wild fish and elevated their [cortisol]plrelative to hatchery fish. Wild fish had the highest APC number among the three groups before the handling. No difference in resistance to Vibrio anguillarum was apparent in coho and chinook salmon among the different rearing environments, although chinook salmon were generally more susceptible; disease resistance was reduced in wild coho salmon after 7 mo of rearing in a hatchery.

Changes in Ouabain-Sensitive Adenosine Triphosphatase Activity in Gills of Coho Salmon (Oncorhynchus kisutch) During Parr–Smolt Transformation

1976 ◽  
Vol 33 (1) ◽  
pp. 54-62 ◽  
Author(s):  
M. A. Giles ◽  
W. E. Vanstone
Keyword(s):  
Enzyme Activity ◽  
Coho Salmon ◽  
Incubation Temperature ◽  
Sea Water ◽  
Oncorhynchus Kisutch ◽  
Sharp Decrease ◽  
Total Activity ◽  
Sodium Ions ◽  
Relative Contribution ◽  
Sodium Activation

The effects of incubation temperature, pH, sodium, potassium, and ATP concentration, and ouabain on the activity of Na+–K+-activated ATPase of the gills of seawater-adapted juvenile coho salmon (Oncorhynchus kisutch) were determined. The temperature and pH optima were 40 C and 7.4, respectively. The apparent Km for ATP at equimolar Mg++ concentration was 0.2 mM at Na+ and K+ concentrations of 100 and 20 mM, respectively. Maximal enzyme activity for Na+ concentration of 10.50 and 100 mM occurred at K+ concentrations of 12.5, 15.0, and 20.0 mM, respectively. The Ki for ouabain was 2 × 10−6 M and 7 × 10−6 for K+ concentrations of 10 and 20 mM, respectively.A large portion (up to 60%) of the ouabain-sensitive ATPase activity in freshwater fish was activated by sodium ions in the absence of potassium ions (Na+-activation). Exposure to sea water resulted in a large increase in total ouabain-sensitive activity and a sharp decrease in the proportion of sodium activation. These changes occurred within 14 days after transfer to full strength sea water.On a seasonal basis, total ouabain-sensitive enzyme activity in juvenile freshwater coho was low (less than 5 μmol Pi/mg N per h) to the end of November, increased to a peak (over 125 μmol Pi/mg N per h) in mid-January, and subsequently declined by late February. A slow, steady rise in activity occurred during the smoking period of March and April and the relative contribution of sodium ions to the total activity declined in this period.

The effects of aroclor 1254 and no. 2 fuel oil on smoltification and sea-water adaptation of coho salmon (Oncorhynchus kisutch)

1982 ◽  
Vol 2 (5-6) ◽  
pp. 291-299 ◽  
Author(s):  
Leroy C. Folmar ◽  
Walton W. Dickhoff ◽  
Waldo S. Zaugg ◽  
Harold O. Hodgins
Keyword(s):  
Coho Salmon ◽  
Sea Water ◽  
Oncorhynchus Kisutch ◽  
Fuel Oil ◽  
Aroclor 1254 ◽  
Sea Water Adaptation

Density-Dependence at Sea for Coho Salmon (Oncorhynchus kisutch)

1990 ◽  
Vol 47 (9) ◽  
pp. 1765-1772 ◽  
Author(s):  
J. M. Emlen ◽  
R. R. Reisenbichler ◽  
A. M. McGie ◽  
T. E. Nickelson
Keyword(s):  
Density Dependence ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Density Dependent ◽  
Density Dependent Mortality ◽  
Hatchery Fish ◽  
Statistical Assumptions ◽  
Diminishing Returns ◽  
Salmon Hatchery ◽  
Dependent Mortality

The success of expanded salmon hatchery programs will depend strongly on the degree of density-induced diminishing returns per smolt released. Several authors have addressed the question of density-dependent mortality at sea in coho salmon (Oncorhynchus kisutch), but have come to conflicting conclusions. We believe there are compelling reasons to reinvestigate the data, and have done so for public hatchery fish, using a variety of approaches. The results provide evidence that survival of these public hatchery fish is negatively affected, directly by the number of public hatchery smolts and indirectly by the number of private hatchery smolts. These results are weak, statistically, and should be considered primarily as a caution to those who, on the basis of other published work, believe that density-dependence does not exist. The results reported here also re-emphasize the often overlooked point that inferences drawn from data are strongly biased by investigators' views of how the systems of interest work and by the statistical assumptions they make preparatory to the analysis of those data.

Potential benefits of a conservation hatchery program for supplementing Oregon coast coho salmon (Oncorhynchus kisutch) populations: a stochastic model investigation

2005 ◽  
Vol 62 (8) ◽  
pp. 1920-1935 ◽  
Author(s):  
Gretchen R Oosterhout ◽  
Charles W Huntington ◽  
Thomas E Nickelson ◽  
Peter W Lawson
Keyword(s):  
Habitat Restoration ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Solution Space ◽  
Oregon Coast ◽  
Hatchery Fish ◽  
Natural Production ◽  
Management Actions ◽  
Genetic Risks ◽  
Hatchery Program

This study developed a stochastic life cycle model to simulate idealized supplementation strategies to investigate the following question: under what circumstances could hatchery fish stocking contribute to the recovery of Oregon coast coho salmon (Oncorhynchus kisutch)? Simulations were used to find a solution space, defined by the attributes of wild and hatchery-bred salmon, their offspring, and their environments, where hatchery fish could supplement natural production without further depressing it until natural or human factors restricting production were relieved. These simulations suggest that short-duration, tightly controlled, low-intensity conservation hatchery programs designed to minimize genetic and ecological risks may yield minor short-term increases in adult coho salmon abundance while posing significant ecological and genetic risks. No solution space was found that indicated clear long-term benefits from such a supplementation program. Of all the management actions modeled, habitat restoration offered by far the largest and only permanent gains in coho salmon abundance while posing no genetic or ecological risk to the fish. The modeled benefits of habitat restoration were significant regardless of assumptions made about the fitness of hatchery fish and their offspring.

Sign in / Sign up

Export Citation Format

Share Document