Osmotic and Ionic Regulation in Scottish Brown Trout and Sea Trout (Salmo Trutta L.)

1959 ◽  
Vol 36 (2) ◽  
pp. 253-260
Author(s):  
MALCOLM S. GORDON
Keyword(s):  
Fresh Water ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Sea Water ◽  
Freezing Point ◽  
Water Levels ◽  
Acid Base Balance ◽  
Serum Samples ◽  
Water Stream ◽  
Sea Trout

1. Adult brown trout (Salmo trutta L.) of both sea-run (sea trout) and fresh-water stream (brown trout) forms were captured in the vicinity of Aberdeen and acclimatized to full-strength sea water for periods of up to 5 months. 2. Blood serum samples from these fish were analysed for freezing-point depression, chloride, sodium and potassium concentrations. 3. The patterns of regulation of these concentrations are very nearly the same in both forms. Brown trout and sea trout, at least in eastern Scotland, thus appear to be virtually identical in osmotic and ionic regulatory abilities. However, there is a possibility that there is a difference between the two forms with respect to mechanisms controlling blood acid-base balance. 4. The patterns of regulation shown by Scottish fish are the same as those shown by American hatchery fish treated similarly. The different populations of the species seem not to have diverged significantly from one another in this regard after many generations of more or less complete genetic isolation. 5. The species Salmo trutta is strongly homoiosmotic. Internal concentrations are either unchanged or increase by less than 10% above fresh-water levels with long-term acclimatizations to half and full sea water. The brown trout is the first salmonid species known to regulate so well.

Ionic Regulation in the Brown Trout (Salmo Trutta L.)

1959 ◽  
Vol 36 (2) ◽  
pp. 227-252 ◽  
Author(s):  
MALCOLM S. GORDON
Keyword(s):  
Fresh Water ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Sea Water ◽  
Extracellular Volume ◽  
Water Levels ◽  
Blood Concentrations ◽  
Brown Trout Salmo Trutta ◽  
Muscle Concentration ◽  
Concentration Changes

1. The osmotic and ionic regulatory abilities of adults of the euryhaline brown trout (Salmo trutta) have been studied in experiments roughly duplicating the stresses of migration from fresh water to the sea. Brown trout will survive indefinitely in full sea water if acclimatized to it at rates inversely related to the temperature. 2. Blood serum samples have been analysed for Na, K, Cl, total P and δ; muscle samples for Na, K, Cl and total solids. Changes in the concentrations of these constituents following transfers from fresh water to 50% and 100% sea have been studied. Transfers were made throughout the year and at temperatures of 10° C. and 20° C. 3. Following transfers to 50% sea water at 20° C. blood concentrations rose significantly above fresh-water levels, but returned very nearly to these levels after about a week. Transfer from 50% sea water to 100% sea water at 20° C. caused the same sequence of changes. Transfer to 100% sea water at 20°C. was fatal, and associated with very high serum concentrations. Many fish survived transfer to 100% sea water at 10°C., however, and showed evidence of internal concentrations returning to fresh-water levels after 10 days. The brown trout is strongly homoiosmotic on a long-term basis. 4. Both survival and regulatory ability were lower during the summer. There were also seasonal variations in the blood and muscle concentrations of fish in a given state of acclimatization. 5. Muscle concentration changes closely paralleled blood changes. Extracellular volume remained constant, so muscle concentration changes were attributable to changes in intracellular water. The muscles did not act as storage sites for sodium and potassium.

scholarly journals Osmoregulation in Salmon and Sea Trout Alevins

1982 ◽  
Vol 101 (1) ◽  
pp. 61-70
Author(s):  
C. TALBOT ◽  
F. B. EDDY ◽  
J. JOHNSTON
Keyword(s):  
Osmotic Stress ◽  
Salmo Trutta ◽  
Developmental Stages ◽  
Electrolyte Concentration ◽  
Sea Water ◽  
Vitelline Membrane ◽  
Turnover Rates ◽  
Progressive Change ◽  
Sea Trout ◽  
Species Survival

Changes in survival, body-water content, body electrolyte concentration and Na+ turnover rates were studied in alevins of Atlantic salmon (Salmosalar L.) and sea trout (Salmo trutta L.) at different developmental stages following exposure to various dilutions of sea water. In 100% sea water, salmon alevins at 9 days post-hatch survived approximately 6 h, and seatrout alevins 13 days post-hatch survived approximately 4 h. In both species, survival in hyperosmotic media decreased and rates of dehydration and Na+ turnover increased with age and development. The progressive change inresistance to osmotic stress is associated with a decrease in body surface area occupied by the relatively impermeable vitelline membrane and to the development of functional gills, leading to an increase in permeability to water and salt.

scholarly journals The Impact of Hydropeaking on Juvenile Brown Trout (Salmo trutta) in a Norwegian Regulated River

2020 ◽  
Vol 12 (20) ◽  
pp. 8670
Author(s):  
Svein Jakob Saltveit ◽  
Åge Brabrand ◽  
Ana Juárez ◽  
Morten Stickler ◽  
Bjørn Otto Dønnum
Keyword(s):  
Power Plant ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Water Levels ◽  
Regulated River ◽  
Low Flow ◽  
High Survival ◽  
Power Station ◽  
Brown Trout Salmo Trutta ◽  
The Impact

The Norwegian electrical energy supply system is based on hydropower. The now deregulated energy market has led to increased use of hydropeaking production, leading to greater fluctuations in discharge and water levels below hydropower stations. The power station HOL 1, with an outlet to the Storåne River, is a large hydropeaking facility. With over 300 rapid flow increases and decreases per year since 2012, it is a river subjected to frequent hydropeaking. To quantify the stranding risk downstream of the power plant, the effect of a series of different turbine shutdown scenarios was simulated in an earlier study. The residual flow of 6 m3·s−1 and a full production of 66 m3·s−1 were considered as the baselines for the calculation of dewatered areas. A three-year study of juvenile fish density both upstream as a reference and downstream of the power plant was undertaken. There were very low densities or even an absence of brown trout (Salmo trutta) older than young-of-the-year (YoY) below the outlet of the power station, despite high densities of YoY in previous years. This is probably due to the large and rapid changes in flow below the power station. Hydropeaking has less impact on the earliest life stages of brown trout during spring and summer, as well as on spawning and egg development during winter. This is attributed spawning in late autumn occurring at a low flow seldom reached during hydropeaking. The high survival of YoY during the first summer and early autumn is likely due to a lower frequency of hydropeaking and higher residual flows, leaving a larger wetted area.

Interpopulation variation in male parr maturation of anadromous brown trout (Salmo trutta) in Norway

1990 ◽  
Vol 68 (9) ◽  
pp. 1983-1987 ◽  
Author(s):  
Jan Henning L'Abée-Lund ◽  
Arne Johan Jensen ◽  
Bjørn Ove Johnsen
Keyword(s):  
Fresh Water ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Mature Male ◽  
Good Growth ◽  
Effective Population ◽  
Poor Growth ◽  
Total Length ◽  
Mature Male Parr ◽  
Smolt Age

We studied male parr maturation in anadromous brown trout in nine Norwegian rivers. Mean age at maturity increased from 1.5 years in southern populations to 5.2 years in northern populations, but the latitudinal correlation was not significant. Mean age of male parr at maturity was negatively correlated with mean total length of 0- and 1-year-old parr. The proportion of mature male parr varied between 0.06 and 0.6 among populations, and was positively correlated with mean total length of 0- and 1-year-old parr. The proportion of mature male parr decreased significantly with increasing mean smolt age of males. This indicates that in populations with relatively poor growth in fresh water (i.e., high smolt age) males mainly spawn as sea-run migrants, whereas in populations with relatively good growth in fresh water the mature male parr potentially contribute twice to the genetic makeup of the population, further increasing the effective population size.

The evolution of under-ice melt ponds, or double diffusion at the freezing point

1974 ◽  
Vol 64 (3) ◽  
pp. 507-528 ◽  
Author(s):  
Seelye Martin ◽  
Peter Kauffman
Keyword(s):  
Fresh Water ◽  
Sea Water ◽  
Freezing Point ◽  
Salt Water ◽  
Ice Sheet ◽  
Water Layer ◽  
Double Diffusion ◽  
Theoretical Models ◽  
Interfacial Region ◽  
Ice Melt

In an experimental and theoretical study, we model a phenomenon observed in the summer Arctic, where a fresh-water layer at a temperature of 0°C floats both over a sea-water layer at its freezing point and under an ice layer. Our results show that the ice growth in this system takes place in three phases. First, because the fresh-water density decreases upon supercooling, the rapid diffusion of heat relative to salt from the fresh to the salt water causes a density inversion and thereby generates a high Rayleigh number convection in the fresh water. In this convection, supercooled water rises to the ice layer, where it nucleates into thin vertical interlocking ice crystals. When these sheets grow down to the interface, supercooling ceases. Second, the presence of the vertical ice sheets both constrains the temperatureTand salinitysto lie on the freezing curve and allows them to diffuse in the vertical. In the interfacial region, the combination of these processes generates a lateral crystal growth, which continues until a horizontal ice sheet forms. Third, because of theTandsgradients in the sea water below this ice sheet, the horizontal sheet both migrates upwards and increases in thickness. From one-dimensional theoretical models of the first two phases, we find that the heat-transfer rates are 5–10 times those calculated for classic thermal diffusion.

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