Development of Salinity Preference in Pre-Smolt Coho Salmon, Oncorhynchus kisutch

1970 ◽  
Vol 27 (4) ◽  
pp. 793-800 ◽  
Author(s):  
Robert G. Otto ◽  
John E. McInerney
Keyword(s):  
Fresh Water ◽  
Coho Salmon ◽  
Sea Water ◽  
Salinity Gradient ◽  
Oncorhynchus Kisutch ◽  
Response Distribution ◽  
Lower Salinity ◽  
Salinity Preference

When tested in a horizontal salinity gradient, freshwater-adapted coho salmon exhibited a bimodal preference response throughout most of the pre-smolt period. Preference modes were located at fresh water and at a salinity intermediate between fresh and sea water. The concentration of the higher preferred salinity changed both with time and instantaneously with the dimensions of the test gradient. Fish tested in a gradient that originated at 4‰ exhibited a single preferred salinity at 7‰ in June, which increased gradually to 13‰ by February. The same fish tested in a gradient originating at fresh water showed a corresponding preference for an intermediate salinity in addition to their preference for fresh water. However, this second preferendum was at a somewhat lower salinity than that observed in tests in which fresh water was excluded from the gradient.With the approach of the smolt transformation, preference for fresh water was greatly reduced and the response distribution became unimodal. At no time during the period prior to the smolt transformation did the preferred salinity exceed 14‰.

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.

scholarly journals Evidence for Freshwater Residualism in Coho Salmon, Oncorhynchus kisutch, From a Watershed on the North Coast of British Columbia

2017 ◽  
Vol 130 (4) ◽  
pp. 336 ◽  
Author(s):  
Eric A Parkinson ◽  
Chris J Perrin ◽  
Daniel Ramos-Espinoza ◽  
Eric B Taylor
Keyword(s):  
British Columbia ◽  
Fresh Water ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Oncorhynchus Kisutch ◽  
Water Levels ◽  
North Coast ◽  
The North ◽  
Seaward Migration ◽  
Mature Fish

The Coho Salmon, Oncorhynchus kisutch, is one of seven species of Pacific salmon and trout native to northeastern Pacific Ocean watersheds. The species is typically anadromous; adults reproduce in fresh water where juveniles reside for 1–2 years before seaward migration after which the majority of growth occurs in the ocean before maturation at 2–4 years old when adults return to fresh water to spawn. Here, we report maturation of Coho Salmon in two freshwater lakes on the north coast of British Columbia apparently without their being to sea. A total of 15 mature fish (11 males and four females) were collected in two lakes across two years. The mature fish were all at least 29 cm in total length and ranged in age from three to five years old. The occurrence of Coho Salmon that have matured in fresh water without first going to sea is exceedingly rare in their natural range, especially for females. Such mature Coho Salmon may represent residual and distinct breeding populations from those in adjacent streams. Alternatively, they may result from the ephemeral restriction in the opportunity to migrate seaward owing to low water levels in the spring when Coho Salmon typically migrate to sea after 1–2 years in fresh water. Regardless of their origin, the ability to mature in fresh water without seaward migration may represent important adaptive life history plasticity in response to variable environments.

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

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.

scholarly journals Hypophysectomy of coho salmon (Oncorhynchus kisutch) and survival in fresh water and seawater

Aquaculture ◽  
1987 ◽  
Vol 65 (3-4) ◽  
pp. 343-352 ◽  
Author(s):  
Richard S. Nishioka ◽  
N.Harold Richman ◽  
Graham Young ◽  
Patrick Prunet ◽  
Howard A. Bern
Keyword(s):  
Fresh Water ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch

Experimental Study on Energy Harvesting From Salinity Gradient by Reverse Electrodialysis in Ag/AgCl Deposited AAO Nanochannel Array

2013 ◽  
Author(s):  
Byeongdong Kang ◽  
Moojoong Kim ◽  
Hyungmin Joo ◽  
Hyun Jung Kim ◽  
Dong-Kwon Kim
Keyword(s):  
Electric Current ◽  
Fresh Water ◽  
Sea Water ◽  
Silver Chloride ◽  
Salinity Gradient ◽  
Rear Surface ◽  
Chemical Oxidation ◽  
Silver Layer ◽  
Reverse Electrodialysis ◽  
Nanochannel Array

Reverse electrodialysis (RED) is energy conversion phenomena which generates electricity from concentration gradient energy by mixing the ions in sea water with fresh water through ion-selective nanochannel. When nanochannels are filled with an aqueous solution, the surface of nanochannels is charged by ionization, ion adsorption, and ion dissolution. Therefore, co-ions are repelled from the nanochannels and only counter-ions can be transported through the nanochannels. As a result, the electric current can be generated by selective ion transport through the nanochannels from sea water to fresh water. Recently, solid-state nanochannels or nanopores have received attention because they have potential to replace polymer ion-selective membranes. Especially, anodic aluminum oxide (AAO) nanochannel array has advantage of easiness of pore size control and high pore density. In the present study, to collect electric current generated by the nanochannels, we deposited the porous silver layer on both front and rear surface of the AAO nanochannel array by using e-beam evaporation and changed the silver layer to the silver/silver chloride layer by chemical oxidation with aqueous FeCl3. Finally, we conduct an experimental investigation for the power generation from the AAO nanochannel arrays placed between two potassium chloride solutions with various combinations of concentrations.

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.

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