Inhibition of Atlantic Salmon (Salmo salar) Hatching at Low pH

1980 ◽  
Vol 37 (5) ◽  
pp. 770-774 ◽  
Author(s):  
R. H. Peterson ◽  
P. G. Daye ◽  
J. L. Metcalfe
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Low Ph ◽  
Hatching Enzyme ◽  
Atlantic Salmon Salmo Salar ◽  
Salmon Eggs ◽  
Perivitelline Fluid ◽  
Eye Pigmentation ◽  
Ambient Levels

Hatching of Atlantic salmon (Salmo salar) eggs was delayed or prevented if they were exposed to water of lowered pH (4.0–5.5) after eye pigmentation had developed. Hatching subsequently could be induced by returning eggs to normal pH levels (6.6–6.8). Perivitelline pH fell rapidly to near ambient levels when eggs were exposed to low pH. It is suggested that the observed effects on hatching were due to inhibition of the hatching enzyme, chorionase.Key words: Atlantic salmon, eggs, pH, perivitelline fluid, chorionase

Influence of Varying pH and some Inorganic Cations on the Perivitelline Potential of Eggs of Atlantic Salmon (Salmo salar)

1984 ◽  
Vol 41 (7) ◽  
pp. 1066-1069 ◽  
Author(s):  
R. H. Peterson
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Incubation Medium ◽  
Ambient Medium ◽  
Ionic Composition ◽  
Potential Difference ◽  
Nernst Equation ◽  
Inorganic Cations ◽  
Atlantic Salmon Salmo Salar ◽  
Perivitelline Fluid

A potential difference is maintained between the perivitelline fluid of the Atlantic salmon (Salmo salar) egg and the incubation medium. The magnitude of this potential difference depends on the ionic composition of the incubation medium; it exhibits a maximal negativity in deionized water, then depolarizes, and finally reverses in sign as the ionic content of the incubation medium is raised. The potential difference obeys the Nernst relationship over a limited concentration range of H+, Ca2+, and Mg2+ (10−5 to 10−3M). The maximal change in potential difference with change in Na+ and K+ concentrations is less than that predicted by the Nernst equation. The potential difference permits calculation of the degree of concentration of cations in the perivitelline fluid over that of the ambient medium. Depolarizing the perivitelline potential by lowering the ambient pH will result in losses of other cations from the perivitelline fluid.

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.

Lack of long-term sublethal effects of reduced freshwater pH alone on Atlantic salmon (Salmo salar) smolts subsequently transferred to seawater

2004 ◽  
Vol 61 (4) ◽  
pp. 511-518 ◽  
Author(s):  
Sveinung Fivelstad ◽  
Anne Berit Olsen ◽  
Sigurd Stefansson ◽  
Sigurd Handeland ◽  
Rune Waagbø ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Sublethal Effects ◽  
Growth Parameters ◽  
Gill Tissue ◽  
Low Ph ◽  
Control Group ◽  
Long Term Effects ◽  
Atlantic Salmon Salmo Salar

Atlantic salmon (Salmo salar) smolts (mean start weight 42 g) in soft freshwater were exposed to three pH ranges (two replicates in each group) for 35 days: pH 6.5–6.8 (control group), pH 5.9–6.3 (medium-pH group), and pH 5.4–5.9 (low-pH group). All exposures had citrate added to remove labile, toxic Al from the water. On day 35, all groups were transferred to 34‰ seawater and kept there for 100 days. H+ was the main stressor in the exposures because labile Al was <6 µg·L–1 and the gill Al was lower than 27 µg·g dry weight–1 (highest in the medium group). The exposure environments did not cause any significant changes to gill tissue structures, gill Na+,-K+-ATPase activity, mortality, and growth parameters during the freshwater period. However, haematocrit was significantly increased and mean plasma chloride was significantly reduced (p < 0.05) in the low-pH group compared with the control group. This study indicated that the H+ concentrations in the pH range 5.4–5.9 in water containing no to little gill-reactive Al do not impact salmon growth and physiology during smoltification. However, the reduction in blood haematocrit in the low-pH group 3 months after seawater transfer may imply long-term effects of the treatment.

Effects of Low Environmental pH on the Survival, Growth, and ionic Composition of Postemergent Atlantic Salmon (Salmo salar)

1985 ◽  
Vol 42 (4) ◽  
pp. 768-775 ◽  
Author(s):  
Gilles L. Lacroix ◽  
D. James Gordon ◽  
Dana J. Johnston
Keyword(s):  
Nova Scotia ◽  
Atlantic Salmon ◽  
River Water ◽  
Salmo Salar ◽  
Ionic Composition ◽  
Low Ph ◽  
Atlantic Salmon Salmo Salar ◽  
Flow Through ◽  
Composition Changes

Postemergent Atlantic salmon (Salmo salar) were reared during the early feeding phase in the soft, acidic water of the Westfield River (mean pH 5.0) in Nova Scotia. The fry were held in a flow-through system of tanks in situ and were fed a hatchery diet. Bioassays were also conducted in river water treated with limestone (mean pH 6.1) to provide a control. Cumulative mortality of fry after 30 d in the tanks was 70% at pH 5.0 and only 4% at pH 6.1. Fry in untreated river water were inactive, ingested little food, and lost weight (approximately 25%) during the first 15 d of exposure. Large increases in body [Ca2+] and [Na+] were observed in fry at both pH levels during that time, but the increase in [Ca2+] lagged and that in [Na+] was less in fry at low pH. Deaths occurred 15–30 d after swim-up and dead fry were all severely emaciated, indicating that deaths were probably from starvation. Although there were differences in ionic composition changes in fry held at pH 5.0 compared with control, no major depletion of body ionic reserves occurred relative to initial concentrations. Surviving fry at pH 5.0 developed a tolerance after 25 d and had growth rates, condition factors, and ionic concentrations similar to those of fry in treated water. The mortality of fry during the transition to exogenous feeding, in response to low pH stress in soft water, is probably responsible for reduced recruitment and the decline or loss of salmon stocks in this and other acidic rivers of Nova Scotia.

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