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

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.

1957 ◽  
Vol 35 (3) ◽  
pp. 371-383 ◽  
Author(s):  
Arthur H. Houston

The responses of chum, Oncorhynchus keta (Walbaum), and pink, O. gorbuscha (Walbaum), salmon fry, and coho, O. kisutch (Walbaum), salmon fry and smolts to sea water were studied in sharp-gradient tanks. Chum and pink fry responded positively to isotonic and hypertonic solutions of sea water, but coho fry only to the former. During parr–smolt transformation, coho responded positively to hypertonic sea water. Responses of chum fry acclimated to sea water for 24 hours prior to observation were comparable in intensity to those of unacclimated fry, but less rapid. Activity of acclimated fry decreased less rapidly than did that of unacclimated fry. Fresh water control experiments indicated the presence of some factor or factors which resulted in preferences for "recognized" areas. The effects of positive responses to increased salinity are discussed in relation to the migratory movement of these species from fresh water into the sea.


1974 ◽  
Vol 31 (1) ◽  
pp. 83-92 ◽  
Author(s):  
J. C. Mason

Chum salmon fry (Oncorhynchus keta) in the estuary of a small coastal stream exploited fresh water, estuarine, and marine food chains and, by so doing, were exposed to marked, daily fluctuations in salinity that demanded active selection of fresh water on ebbing tides day and night. The resulting delay in seaward migration and associated behavioral observations are inadequately reflected in published accounts of the life history and behavior of chum fry in natural systems and laboratory situations, and the downstream displacement theory. The biological basis for delayed seaward migration of chum fry merits the attention of fishery researchers and resource managers alike.


1959 ◽  
Vol 37 (4) ◽  
pp. 591-605 ◽  
Author(s):  
Arthur Hillier Houston

Transfer into sea water produced an immediate and marked depression of the cruising speed of chum salmon fry. Despite considerable recovery from this initial effect the fish exhibited a continuing slight depression of cruising speed over the entire experimental period (80 hours). Variations in total body levels of chloride and water were significantly correlated with changes in cruising speed, suggesting that variations in activity might be related to the process of osmoregulatory adaptation to sea water. Possible mechanisms underlying this effect have been discussed.


1982 ◽  
Vol 39 (3) ◽  
pp. 509-514 ◽  
Author(s):  
Munehico Iwata ◽  
Sanae Hasegawa ◽  
Tetsuya Hirano

Chum salmon (Oncorhynchus keta) fry weighing about 1 g maintained plasma Na+ concentrations at 134–140 mmol/L during seaward migration in the Otsuchi River. The plasma Na+ level increased slightly in the estuary, and reached 150–160 mmol/L in the fry caught in the bay. On direct transfer from freshwater to seawater, the plasma Na+ concentrations of the fry weighing 0.4–2.3 g increased markedly after 1 h and reached a maximum after 3–12 h. The fry of < 1.4 g attained sea water-acclimated plasma Na+ level of 156 mmol/L within 24 h after transfer, whereas fry of 1.8–2.3 g failed to adapt to seawater within 24 h. When seawater adaptability of fry of different lots was examined simultaneously in late April, 83–109 d after hatch, the smaller fry adjusted their plasma Na+ levels more easily than the larger fry: the smallest fry attained seawater level after 12 h without showing any peak. Changes in seawater adaptability of the same lots of fry were also followed until 5 mo after hatching, and the osmoregulatory ability of the fry in seawater decreased gradually with an increase in body weight or in the time spent in freshwater.Key words: chum salmon fry, seaward migration, plasma Na+ concentration, seawater adaptability, Oncorhynchus keta


1987 ◽  
Vol 44 (2) ◽  
pp. 236-243 ◽  
Author(s):  
Kurt L. Fresh ◽  
Steven L. Schroder

Predator–prey interactions between juvenile chum salmon (Oncorhynchus keta) and piscivores were studied in a small coastal stream and in sections of a controlled-flow channel. The predators were primarily large [Formula: see text] rainbow trout (Salmo gairdneri) and large [Formula: see text] coho salmon (O. kisutch). The relationship between chum salmon fry abundance and the quantity consumed by predators suggested a type II functional response. Neither prey size nor prey abundance influenced predation, but predators did select fry with relatively high yolk reserves. Our results suggest that the numbers of juvenile chum salmon needed to satiate predators and to enhance fry survival are attainable by enhancement projects located on smaller rivers and streams.


1966 ◽  
Vol 23 (2) ◽  
pp. 293-304 ◽  
Author(s):  
J. E. Shelbourn

Underyearling chum fry from hatchery stock were held in fresh water and salt water at two different temperatures and under two different photoperiods and acclimated to these conditions for 40 days before testing started. Aggregations were greater in salt water than in fresh water (p <.01). Fish acclimated to cold water schooled more strongly than those acclimated to warm water but this effect was not considered statistically significant. There were no differences in intensity of aggregation due to photoperiod (p >.05). The significance of these findings is discussed in relation to life history of the fry.


1989 ◽  
Vol 46 (8) ◽  
pp. 1396-1405 ◽  
Author(s):  
L. Blair Holtby ◽  
Thomas E. McMahon ◽  
J. Charles Scrivener

Variability in average stream temperatures between peak spawning and fry emergence accounted for 82 and 77% of the variance in the median emigration date of fry of chum (Oncorhynchus keta) and coho salmon (O. kisutch) respectively over a 9 to 10-yr period. The modeled relationships were indistinguishable from laboratory models that predicted time to maximum alevin wet weight. Variability in stream temperatures during the spring accounted for 60% of the variability in the median date of coho smolt emigration. As stream temperatures increased, the predicted thermal summations required for emigration were nearly constant for coho salmon fry, increased moderately for chum salmon fry and increased strongly for coho salmon smolts The duration of the emigration period also differed between the groups: 50% of the chum salmon fry emigrated over a 1-wk period compared with a 2- to 3-wk period for coho salmon fry and smolts. We speculate that the emigration timing —temperature relationships and timing of adult spawning represent adaptations for synchronizing emigration with "windows of opportunity" in the ocean or stream. The windows are of different widths and levels of predictability for coho and chum salmon fry and coho salmon smolts.


1968 ◽  
Vol 48 (2) ◽  
pp. 359-380
Author(s):  
D. W. SUTCLIFFE

1. Sodium uptake and loss rates are given for three gammarids acclimatized to media ranging from fresh water to undiluted sea water. 2. In Gammarus zaddachi and G. tigrinus the sodium transporting system at the body surface is half-saturated at an external concentration of about 1 mM/l. and fully saturated at about 10 mM/l. sodium. In Marinogammarus finmarchicus the respective concentrations are six to ten times higher. 3. M. finmarchicus is more permeable to water and salts than G. zaddachi and G. tigrinus. Estimated urine flow rates were equivalent to 6.5% body weight/hr./ osmole gradient at 10°C. in M. finmarchicus and 2.8% body weight/hr./osmole gradient in G. zaddachi. The permeability of the body surface to outward diffusion of sodium was four times higher in M. finmarchicus, but sodium losses across the body surface represent at least 50% of the total losses in both M. finmarchicus and G. zaddachi. 4. Calculations suggest that G. zaddachi produces urine slightly hypotonic to the blood when acclimatized to the range 20% down to 2% sea water. In fresh water the urine sodium concentration is reduced to a very low level. 5. The process of adaptation to fresh water in gammarid crustaceans is illustrated with reference to a series of species from marine, brackish and freshwater habitats.


PEDIATRICS ◽  
1966 ◽  
Vol 37 (4) ◽  
pp. 684-698
Author(s):  
Jerome Imburg ◽  
Thomas C. Hartney

Animal studies have shown that fluid enters the body via the lungs in sea-water and fresh-water drowning. In fresh-water drowning in dogs, there is marked and rapid hemodilution with death due to ventricular fibrillation in about 4 minutes. In sea-water drowning in dogs, there is hemoconcentration; the blood water is lost into the sea water in the lungs with bradycardia and death due to asystole in 6 to 8 minutes. Studies of human drowning victims show similar, but less striking, changes in hemodynamics. In human non-fatal submersion the problems are usually those produced by impaired pulmonary function and central nervous system damage due to hypoxia. Hemodilution and ventricular fibrillation have not been documented in human nonfatal submersion. Therapeutic measures may be divided into those of an immediate urgent nature to be employed at the accident scene: expired air resuscitation, which should be started on reaching the unconscious victim in the water, and external cardiac massage, when indicated. Later measures to be instituted in the hospital include: cardiac resuscitation, intermittent positive-pressure breathing, hypothermia, tracheostomy and tracheal tiolet, oxygen therapy, antibiotics, steroids, and intravenous fluids to correct defects in blood elements (hemoglobin, electrolytes, pH). Later, pulmonary function should be studied for impairment due to alveolar damage and fibrosis. Permanent neurologic sequellae may develop.


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