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.

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.

Kinetics of Water and Chloride Exchanges During Adaptation of the European Eel to Sea Water

1973 ◽  
Vol 58 (1) ◽  
pp. 105-121
Author(s):  
R. KIRSCH ◽  
N. MAYER-GOSTAN
Keyword(s):  
Fresh Water ◽  
Sea Water ◽  
Anguilla Anguilla ◽  
Maximum Level ◽  
Progressive Increase ◽  
Plasma Sodium ◽  
European Eel ◽  
Drinking Rate ◽  
The One ◽  
Kinetics Of

Using isotopic procedures, the drinking rate and chloride exchanges were studied in the eel Anguilla anguilla during transfer from fresh water to sea water. 1. Following transfer to sea water there is a threefold increase of the drinking rate (lasting about 1 h). Then it falls to a minimum after 12-16 h and rises again to a maximum level about the seventh day after the transfer. Then a gradual reduction leads to a steady value which is not significantly different from the one observed in fresh water. 2. The changes with time of the plasma sodium and chloride concentrations are given. Their kinetics are not completely alike. 3. The chloride outflux increases 40-fold on transfer of the eel to sea water, but even so it is very low. After the sixth hour in sea water there is a progressive increase in the flux, so that on the fourth day it is higher (500 µ-equiv. h-1.100 g-1) than in the seawater-adapted animals (230 µ-equiv.h-1.100 g-1). 4. Drinking rate values in adapted animals are discussed in relation to the external medium. The kinetics of the drinking rate together with variations in body weights after freshwater-seawater transfer are discussed in relation to the possible stimulus of the drinking reflex. 5. Chloride fluxes (outflux, net flux, digestive entry) are compared and lead one to assume that in seawater-adapted fish one-third of the chloride influx enters via the gut and two-thirds via the gills.

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.

THE OSMOREGULATORY ROLE OF THE THYROID GLAND IN THE STARRY FLOUNDER, PLATICHTHYS STELLATUS

1959 ◽  
Vol 37 (6) ◽  
pp. 997-1060 ◽  
Author(s):  
Cleveland P. Hickman Jr.
Keyword(s):  
Thyroid Gland ◽  
Fresh Water ◽  
Body Fluid ◽  
Sea Water ◽  
Salt Water ◽  
Standard Metabolic Rate ◽  
Energy Demands ◽  
Platichthys Stellatus ◽  
Fluid Concentration

Energy demands for osmotic regulation and the possible osmoregulatory role of the thyroid gland were investigated in the euryhaline starry flounder, Platichthys stellatus. Using a melting-point technique, it was established that flounder could regulate body fluid concentration independently of widely divergent environmental salinities. Small flounder experienced more rapid disturbances of body fluid concentration than large flounder after abrupt salinity alterations.The standard metabolic rate of flounder adapted to fresh water was consistently and significantly less than that of marine flounder. In supernormal salinities standard metabolic rate was significantly greater than in normal sea water. These findings agree with the theory that energy demands for active electrolyte transport are greater in sea water than fresh water.Thyroid activity was studied in flounder adapted to fresh water and salt water. Percentage uptake of radioiodine by the thyroid was shown to be an insensitive and inaccurate criterion for evaluating thyroid activity in different salinities because removal rates of radioiodine from the body and blood differed between fresh water and marine flounder. Using thyroid clearance of radioiodine from the blood as a measure of activity, salt-water flounder were shown to have much greater thyroid clearance rates and, hence, more active thyroid glands than flounder adapted to fresh water. The greater activity of the thyroid of marine flounder correlates with greater oxygen demands in sea water and suggests a direct or adjunctive osmoregulatory role of the thyroid gland of fish.

Studies on Salt-Water and Fresh-Water Anopheles gambiae on the East African Coast

1951 ◽  
Vol 41 (3) ◽  
pp. 487-502 ◽  
Author(s):  
R. C. Muirhead Thomson
Keyword(s):  
West Africa ◽  
Fresh Water ◽  
Sea Water ◽  
Salt Water ◽  
Dar Es Salaam ◽  
Limiting Factor ◽  
East African ◽  
East African Coast ◽  
African Coast ◽  
Gravid Females

The brackish water form of A. gambiae on the East African coast—and probably in Mauritius—is not the same as A. melas of West Africa.In salt-water gambiae a variable proportion of the females have an additional dark band on the palps, resembling 4-banded melas, but the remainder are indistinguishable from typical gambiae.Eggs and larvae of salt-water gambiae show no morphological differences from those of fresh-water gambiae, thereby differing from A. melas of West Africa.Larvae of the two forms show a clear-cut difference in reaction to sudden changes in salinity, and a simple test has been worked out whereby wild-caught females can be accurately identified by the reactions of their progeny.This physiological test has formed the basis of all work in comparing the incidence, habits, and infectivity of salt and fresh-water gambiae in Dar-es-Salaam.Exposed to equal chances of infection in the same village during 1947 and 1948, fresh-water gambiae had a sporozoite rate of 9·4 per cent. while that of salt-water gambiae was 0·8 per cent.About 4 per cent, of both forms were infected with filaria larvae, but monthly figures showed that infection rates in salt-water gambiae may rise to 22 per cent.Fresh-water gambiae show little tendency to leave African houses at dawn after feeding, whereas in salt-water gambiae over one-third of freshly blood-fed females leave the house at dawn.In fresh-water gambiae many half-gravid females leave the shelter of the house at dusk on the night after the blood feed. There is no marked difference in infectivity between those which leave the hut and those which remain indoors at this stage.Blood-fed and gravid females of fresh-water gambiae, funestus, and salt-water gambiae have been found in outdoor resting places, gravid females predominating in the case of the first two.Although larvae of salt-water gambiae can complete their development in pure sea water, in nature increasing salinity becomes a limiting factor before it reaches that of sea water, continuous breeding being no longer possible at salinities over 83 per cent. sea water.Salinity as a limiting factor explains the rather restricted breeding of salt-water gambiae on the coast, and suggests that certain coastal fresh-water swamps at Dar-es-Salaam could be cleared of all Anopheline breeding by salinifying with sea water.

scholarly journals The Adaptation of Mosquito Larvae to Salt Water

1933 ◽  
Vol 10 (1) ◽  
pp. 27-36 ◽  
Author(s):  
V. B. WIGGLESWORTH
Keyword(s):  
Basement Membrane ◽  
Fresh Water ◽  
Mosquito Larva ◽  
Sea Water ◽  
Salt Water ◽  
Physiological Adaptation ◽  
Mosquito Larvae ◽  
Salt Solutions ◽  
Newly Hatched Larvae

Larvae of Aedes argenteus reared in fresh water are killed by 1.1 per cent. NaCl or by "sea water"1 isotonic with 1.3-1.4 per cent. NaCl. Newly hatched larvae are killed by 1.1 per cent. NaCl or "sea water" equivalent to 1.3 per cent. NaCl. By gradually increasing the concentration, larvae can be made resistant to 1.1 per cent. NaCl and to "sea water" equivalent to 1.75 percent. NaCl (50 per cent. sea water). The nature of the physiological adaptation in these larvae has been studied and the following conclusions reached: 1. The elastic strands in the cells of the gills become exaggerated, and these cells resist swelling in hypertonic salt solutions. 2. There are changes in the epithelium of the mid-gut so that: (a) the cells are no longer caused to swell up and become detached from the basement membrane; and (b) the mid-gut and caeca can absorb the salt fluid and so avoid the excessive distension which occurs in unadapted larvae. 3. It is possible that the Malpighian tubes excrete a more concentrated urine and that the reabsorptive activity of the rectum is increased. The mosquito larva appears to be homoiosmotic in both fresh water and in hypertonic salt water.

Lung changes and incidence of respiratory arrest in rats after aspiration of sea and fresh water

1961 ◽  
Vol 16 (1) ◽  
pp. 41-44 ◽  
Author(s):  
Denis F. J. Halmagyi
Keyword(s):  
Body Weight ◽  
Fresh Water ◽  
Sea Water ◽  
Salt Water ◽  
Respiratory Arrest ◽  
Fluid Administration ◽  
Lung Weight ◽  
Intratracheal Administration ◽  
Cervical Vagotomy

Some effects of intratracheal administration of 0.1 ml/100 gm body weight of fresh and sea water were studied in intact and vagotomized rats. No local changes were seen in the lungs after fresh water inhalation. A marked increase in lung weight and intra-alveolar hemorrhages developed following the aspiration of sea water. Fatal respiratory arrest occurred in some cases of salt water and cold fresh water inhalation. Bilateral cervical vagotomy prior to the intratracheal fluid administration failed to affect the incidence of respiratory arrest. Submitted on November 30, 1959

Effect of Dietary Sodium Chloride on Growth of Atlantic Salmon (Salmo salar)

1975 ◽  
Vol 32 (10) ◽  
pp. 1813-1819 ◽  
Author(s):  
H. M. Shaw ◽  
R. L. Saunders ◽  
H. C. Hall ◽  
E. B. Henderson
Keyword(s):  
Sodium Chloride ◽  
Atlantic Salmon ◽  
Fresh Water ◽  
Salmo Salar ◽  
Sea Water ◽  
Dietary Sodium ◽  
Plasma Sodium ◽  
Food Conversion ◽  
Dietary Salt ◽  
Dietary Sodium Chloride

Growth and food conversion efficiency in Atlantic salmon smolts (Salmo salar) in either fresh water or sea water were not demonstrably affected by varying the level of dietary sodium chloride. Large dietary salt loads were almost completely absorbed from the gastrointestinal tracts offish within 24 h, and plasma sodium and chloride concentrations were positively affected at this time.Irrespective of whether fish were undergoing random, spontaneous activity or an enforced, uniform low level of activity, growth rates and food conversion efficiencies were similar when fish were fed the same ration but different amounts of sodium chloride.A possible explanation is that normal renal function in fresh water provides for large amounts of hypoosmotic urine in which excess sodium chloride may be discharged without great expenditure of energy. However, in sea water, where urine flow is minimal, the main route of excretion for the excess electrolytes is across the gills, a process requiring energy.

THE SHIFT IN VISUAL PIGMENT DOMINANCE IN THE RETINAE OF JUVENILE COHO SALMON (ONCORHYNCHUS KISUTCH): AN INDICATOR OF SMOLT STATUS

1994 ◽  
Vol 195 (1) ◽  
pp. 185-197 ◽  
Author(s):  
G Alexander ◽  
R Sweeting ◽  
B Mckeown
Keyword(s):  
Visual Pigment ◽  
Coho Salmon ◽  
Sea Water ◽  
Early Summer ◽  
Plasma Sodium ◽  
Pigment Composition ◽  
Steady Decrease ◽  
The Relationship ◽  
Vitamin A2 ◽  
Osmoregulatory Ability

Smolting juvenile coho salmon were sampled to determine (1) whether a correlation between hypo-osmoregulatory ability and visual pigment composition existed and (2) whether the hormone 3,5,3'-tri-iodothyronine (T3) was playing a role in the visual pigment conversion process. Plasma sodium levels of seawater-challenged fish (30 ) indicated that there was a 5 week period of optimal ability to excrete excess plasma sodium ions (hypo-osmoregulation) in the late spring/early summer that represented the 'window of opportunity' for the entry or introduction to sea water of the salmon. Early in the smoltification process, the vitamin-A2-based visual pigment porphyropsin increased its dominance in the retinae, and radioimmunoassay of plasma indicated that T3 levels were at a maximum prior to this increase in porphyropsin. As the parr­smolt transformation continued, there was a steady decrease in the relative amounts of porphyropsin, indicating that the retinae were favouring the acquisition of rhodopsin. Rhodopsin dominance virtually coincided with the period of best hypo-osmoregulatory ability. Subsequently, the salmon showed a loss of hypo-osmoregulatory ability and concomitant increases in the amount of porphyropsin in the retina were observed. The relationship between the visual pigment shift and the smoltification process is discussed in terms of preparation for migration and thyroid hormone involvement, and the use of retinal visual pigment composition as an index of smolt status is proposed.

Changes in Body Chloride, Density, and Water Content of Chum (Oncorhynchus keta) and Coho (O. kisutch) Salmon Fry when Transferred from Fresh Water to Sea Water

1951 ◽  
Vol 8b (3) ◽  
pp. 164-177 ◽  
Author(s):  
Virginia Safford Black
Keyword(s):  
Water Content ◽  
Fresh Water ◽  
Chum Salmon ◽  
Coho Salmon ◽  
Sea Water ◽  
The Body ◽  
Oncorhynchus Keta ◽  
Normal Range ◽  
Experimental Conditions ◽  
Salmon Fry

Changes in body chloride, density and water content of chum and coho salmon fry were measured when these fish were transferred from fresh water to sea water, and the reverse. Both species tolerated 50% sea water (8–9‰ Cl). Chum fry survived direct transfer from fresh water to sea water (15–17‰ Cl), but showed a marked increase in body chloride during the first 12 hours, followed by a return to the normal range between 12 and 24 hours. Coho, however, died within the first 36 hours, after a 60% increase in chloride. Coho fry lost more water than chum fry after introduction to sea water. The density of both species approximated that of the water within an hour of transfer to the new medium. When returned to fresh water after 12 hours in sea water the body chloride, density, and water content of both species regained normal levels within 10 hours. Chum salmon go to sea as fry, whereas cohos remain in fresh water a year or more. Although coho fry seem capable of some adjustment to sea water after a preliminary period in 50% sea water, permanent acclimatization could not be demonstrated under the experimental conditions.

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