Effects of Acid Water and Aluminum on Parr–Smolt Transformation and Seawater Tolerance in Atlantic Salmon, Salmo salar

1993 ◽  
Vol 50 (9) ◽  
pp. 1816-1827 ◽  
Author(s):  
Magne Staurnes ◽  
Per Blix ◽  
Ola B. Reite
Keyword(s):  
Carbonic Anhydrase ◽  
Atlantic Salmon ◽  
Atpase Activity ◽  
Salmo Salar ◽  
Carbonic Anhydrase Activity ◽  
Low Ph ◽  
Soft Water ◽  
Control Fish ◽  
Exposed Fish ◽  
Seawater Tolerance

Smolting Atlantic salmon, Salmo salar, were kept from 11 April to 24 May in soft water of pH 5 or in soft water of pH 5 and 50 μg aluminum (Al)∙L−1. Control fish were kept in soft water of pH 6.3–6.5. Water temperature was 8–14 °C. In mid-May, some of the control smolts were transferred to the test conditions for 8 d. Exposure to acid water resulted in osmoregulatory failure and high mortality rate. Al strongly enhanced toxicity. Sensitivity to low pH or low pH/Al exposure greatly increased when fish had developed to seawater tolerant smolts. In control and acid-exposed fish, gill carbonic anhydrase activity remained unchanged throughout the experiment whereas in Al-exposed fish, carbonic anhydrase activity decreased. Gill Na+K+-ATPase activity in control fish peaked in mid-May simulanteously with development of seawater tolerance. Fish from both acid-exposed groups had low seawater tolerance. Na+,K+-ATPase activity declined to 60% of start value in acid-exposed fish and to parr level in Al-exposed fish. Hypoosmoregulatory ability was linearly correlated with gill Na+K+-ATPase activity. Reduction in plasma Na+ concentration in acid-exposed fish was linearly correlated with the reduction in gill Na+,K+-ATPase activity.

Effect of Photoperiods on the Reactions of Juvenile Atlantic Salmon (Salmo salar L.) to Light Stimuli

1963 ◽  
Vol 20 (5) ◽  
pp. 1245-1266 ◽  
Author(s):  
A. T. Pinhorn ◽  
C. W. Andrews
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Light Stimulus ◽  
Continuous Light ◽  
Control Fish ◽  
Intermittent Light ◽  
Exposed Fish ◽  
Juvenile Atlantic Salmon ◽  
Light Stimuli ◽  
Increased Activity

The reactions to light stimuli of juvenile Atlantic salmon exposed to photoperiods (light-exposed fish) and those exposed to control conditions (control fish) were compared. The light-exposed fish showed more activity and reacted more readily to stimuli than the control fish. Both the control and light-exposed fish exhibited a negative phototaxis at all light intensities except the very lowest where a slight positive phototaxis was obvious. The intensity of an intermittent light stimulus had very little effect on the intensity of the reaction in the light-exposed fish, while the control fish showed an increase in the intensity of the reaction with an increase in the intensity of the light stimulus. The control fish showed an increase in the reaction to the intermittent light stimulus the longer the stimulus was applied at the higher levels of stimulation, while the light-exposed fish showed this behavior at the lower levels of stimulation. The reactions to continuous light were similar to the reactions to intermittent light stimuli, but the light-exposed fish reacted more quickly to continuous light than the control fish. These differences in behavior are attributed to the increased activity and sensitivity of the light-exposed fish, resulting from their exposure to photoperiods.

Effects of Low Environmental pH on Smolting of Atlantic Salmon (Salmo salar)

1983 ◽  
Vol 40 (8) ◽  
pp. 1203-1211 ◽  
Author(s):  
Richard L. Saunders ◽  
Eugene B. Henderson ◽  
Paul R. Harmon ◽  
C. Edward Johnston ◽  
J. Geoffrey Eales
Keyword(s):  
Atlantic Salmon ◽  
Atpase Activity ◽  
Salmo Salar ◽  
Constant Temperature ◽  
Water Hardness ◽  
Low Ph ◽  
Temperature Plasma ◽  
Atlantic Salmon Salmo Salar ◽  
Temperature Regimes ◽  
And Control

We reared Atlantic salmon (Salmo salar) in soft water (hardness 13 mg/L as CaCO3) at two pH levels, 6.4–6.7 and 4.2–4.7, from February to June, to assess the effect of low pH on survival, growth, and the smolting process under rising (4–8.5 °C) or relatively constant (9.5–10.5 °C) temperature. Survival was lower as a result of low pH (4.2–4.7) under both temperature regimes. Neither group exposed to low pH gained weight whereas both control groups gained weight during the experiment. Parr–smolt transformation, as indicated by salinity tolerance and gill Na+, K+ ATPase activity, was impaired as a result of low pH. The large (17–19 cm) parr used in this study were initially salinity tolerant and those at control pH (6.4–6.7) increased tolerance to 35‰ salinity between March and May; those in low pH became intolerant of high salinity. ATPase levels in salmon reared at low pH were significantly lower than those at normal pH levels under both temperature regimes. ATPase activity was significantly greater in fish reared at pH 6.4–6.7 with rising than with constant temperature. Plasma chloride and sodium levels were low in response to low pH, indicating impaired ionic regulation in freshwater. Plasma calcium levels were higher at low pH in both temperature regimes; higher levels were reached under constant temperature. Moisture content rose less sharply under low than under control pH in both temperature regimes. In the rising temperature regime, lipid levels reached similar, low levels under low and control pH conditions. Thyroid hormone (T3 and T4) levels gave no clear indication of effects of low pH on smolting. Smoltification did not proceed normally in our Atlantic salmon subjected to low pH levels.

The effect of porcine somatotropin on growth, and survival in seawater of Atlantic salmon (Salmo salar) parr

1976 ◽  
Vol 54 (4) ◽  
pp. 531-535 ◽  
Author(s):  
M. P. Komourdjian ◽  
R. L. Saunders ◽  
J. C. Fenwick
Keyword(s):  
Growth Hormone ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Growth Hormone Treatment ◽  
Hormone Treatment ◽  
Control Fish ◽  
Growth And Survival ◽  
Atlantic Salmon Salmo Salar ◽  
Porcine Somatotropin

The effects of porcine growth hormone on growth and salinity tolerance were studied in Atlantic salmon (Salmo salar) parr. Fish were held in freshwater at 11.5 °C during June and July under a photoperiod with light to dark periods opposite to the prevailing natural conditions. Fish treated with 1.0 μg/g body weight of growth hormone preparation on alternate days were significantly longer (P <.05), after 4 weeks, than placebo-injected controls. All hormone-injected fish survived transfer to seawater, 30‰ salinity. But under the same conditions, placebo-injected control fish showed a high mortality rate. Growth-hormone treatment caused a darkening of fin margins and a yellowing of the operculae and fin surfaces. The silvering which normally accompanies smoltification was not observed. The role of growth hormone in eliciting these actions and its possible role in the parr–smolt transformation are discussed.

Genetic, Environmental, and Maturational Effects on Atlantic Salmon (Salmo salar) Survival in Acute Low pH Trials

1986 ◽  
Vol 43 (8) ◽  
pp. 1547-1555 ◽  
Author(s):  
C. B. Schom
Keyword(s):  
Atlantic Salmon ◽  
Survival Time ◽  
Salmo Salar ◽  
Dominant Gene ◽  
Low Ph ◽  
Research Centre ◽  
First Year ◽  
Significant Component ◽  
Salmon River ◽  
Mature Parr

Wild sea-run anadromous salmon (Salmo salar) were captured in Big Salmon River in New Brunswick and transported to the Atlantic Salmon Federation's research centre for spawning. Four year-classes were established, one each in 1980, 1981, 1982, and 1983, using a nested design, i.e. one female with one anadromous male and one or two mature parr. The mature parr, in all but the first year, were from families identified as to survival time in acute low pH trials. Resistance to low pH, i.e. survival time, was family specific and independent of the trial conditions. The heritabilities had dominant and additive components with, however, the apparent larger dam than sire effect an artifact of the experimental design. The most significant component appeared to be the dominant gene component. The mature parr were more resistant than the nonmature parr. Finally, genetic gains from selection were much greater in the down direction than the up direction, and this appeared to be a consequence of negative hatchery selection.

Effects of Diet or Liming on Steroid Hormone Metabolism and Reproduction in Atlantic Salmon (Salmo salar) Held in an Acidic River

1990 ◽  
Vol 47 (12) ◽  
pp. 2422-2430 ◽  
Author(s):  
G. B. Sangalang ◽  
H. C. Freeman ◽  
J. F. Uthe ◽  
L. S. Sperry
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Reproductive Performance ◽  
Steroid Hormone ◽  
Control Fish ◽  
Dietary Salt ◽  
Hormone Metabolism ◽  
Atlantic Salmon Salmo Salar ◽  
Water Ph ◽  
Acidic River

Attempts to avert the impacts of an acidic river environment on Atlantic salmon (Salmo salar) were carried out in 1985 and 1986. Salmon were held in the Westfield River (pH 4.7–5.2) and the nearby Medway River (pH 5.3–5.6) during their sexual maturation. A diet containing 3% NaCl was fed to the Westfield salmon in 1985. Marble chips were used to elevate the pH of Westfield River water in 1986. Fish fed the salt diet had higher peak levels of plasma sex hormones, higher fecundity, greater incidence of spawners, lower egg mortality, and less weight loss than fish fed a commercial trout diet. The reproductive performance of fish held in limed water (pH 5.1–5.9) almost attained the level observed in the Medway (control) fish. Limestone treatment stimulated early peaking of blood androgen levels, testosterone, and 11-ketotestosterone in Westfield males, and 17α, 20β-dihydroxy-4-pregnen-3-one, a follicular mediator of gonadotropin, in a few Westfield females. The head kidneys produced more cortisol and corticosterone in all Westfield fish in both years compared to Medway fish. The results suggest that neither dietary salt nor liming completely prevented the decline of reproductive performance and the alteration of steroid hormone metabolism in salmon.

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