Development of Atlantic Salmon (Salmo salar) Eggs and Alevins Under Varied Temperature Regimes

1977 ◽  
Vol 34 (1) ◽  
pp. 31-43 ◽  
Author(s):  
R. H. Peterson ◽  
H. C. E. Spinney ◽  
A. Sreedharan
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Yolk Sac ◽  
Optimum Temperature ◽  
Atlantic Salmon Salmo Salar ◽  
Temperature Regimes ◽  
Varied Temperature ◽  
Eye Pigmentation ◽  
Incubation Temperatures

Atlantic salmon (Salmo salar) eggs and alevins were raised under conditions where the temperature was systematically varied either at fertilization, at the eyed egg stage, or at hatching. Mortality was more than 20% in eggs started immediately after fertilization at constant incubation temperatures < 4 °C as compared with 5% or less at temperatures > 4 °C. Alevins that eyed at 8 °C and higher were progressively smaller the higher the temperature. The optimum temperature from fertilization to eye pigmentation was near 6 °C. Eyed eggs reared at lower temperatures until hatching were larger than those hatched at higher temperatures. This size differential was maintained until the yolk was completely absorbed at all posthatching temperatures investigated. Sudden decreases in temperature at the eyed egg and hatching stages induced severe edema of the alevin yolk sac, resulting in slower growth and increased mortality.

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

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.

Yolk Absorption, Yolk Sac Constrictions, Mortality, and Growth During First Feeding of Atlantic Salmon (Salmo salar) Incubated on Astro-turf

1985 ◽  
Vol 42 (6) ◽  
pp. 1073-1078 ◽  
Author(s):  
T. J. Hansen ◽  
D. Møller
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Lateral Force ◽  
Yolk Sac ◽  
Artificial Substrate ◽  
Feeding Period ◽  
Atlantic Salmon Salmo Salar ◽  
First Feeding ◽  
Flat Screen ◽  
Yolk Absorption

Groups of pooled Atlantic salmon (Salmo salar) eggs were incubated in a "California" incubation system with and without astro-turf, an artificial substrate, and later transferred to separate feeding units. Alevins reared in astro-turf absorbed their yolk sac faster and more efficiently than alevins reared on a flat screen. Alevins reared on the flat screen developed yolk sac constrictions probably due to the backward and lateral force created by the high swimming activity. No such malformations were found on the yolk sacs of the astro-turf reared alevins. The fry hatched without astro-turf grew faster than the fry hatched with astro-turf during the initial feeding period, but later this was reversed. Mortality of alevins and fry hatched with astro-turf was lower during incubation and during first feeding.

Genetic variability in reaction norms between farmed and wild backcrosses of Atlantic salmon (Salmo salar)

2009 ◽  
Vol 66 (1) ◽  
pp. 83-90 ◽  
Author(s):  
Tamara L. Darwish ◽  
Jeffrey A. Hutchings
Keyword(s):  
Genetic Variability ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Second Generation ◽  
Common Garden ◽  
Early Life History ◽  
Reaction Norms ◽  
Adaptive Responses ◽  
Atlantic Salmon Salmo Salar ◽  
Temperature Regimes

Adaptive responses to environmental heterogeneity may vary among populations. Genetic variability in reaction norms might account for population differences in the ability to respond to environmental change and may reflect local adaptation. Reaction norms for early life history traits were compared among three population crosses of Atlantic salmon ( Salmo salar ). Two comprised second-generation backcrosses introgressed with either farmed or wild genes; the third comprised individuals from a second-generation, pure wild cross. Using a common-garden experimental protocol, each cross was exposed to three temperature regimes. Plasticity in embryonic development, growth, survival, and body size was measured from fertilization up to 24 weeks of exogenous feeding. Reaction norms differed markedly among crosses, irrespective of whether individuals interbred with those whose genes originated from another wild population or from a cultured population. We find that introgression involving individuals with comparatively few genetic differences can change reaction norms. If plasticity represents an adaptive response to local environments, then changes to reaction norms resulting from interbreeding between populations are unlikely to have a beneficial effect on fitness.

Incubation of the Eggs of Atlantic Salmon, Salmo salar, at Low Temperatures

1984 ◽  
Vol 41 (2) ◽  
pp. 389-391 ◽  
Author(s):  
Tor G. Heggberget ◽  
Jeff C. Wallace
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Temperature Regime ◽  
Low Temperatures ◽  
Degree Days ◽  
Northern Norway ◽  
The Third ◽  
Atlantic Salmon Salmo Salar ◽  
Temperature Regimes ◽  
Exact Timing

Eggs of Atlantic salmon (Salmo salar) from the River Alta in northern Norway were subjected to three experimental temperature regimes during prehatching incubation. Two of these were intended to simulate possible temperature situations in the river after hydroelectrical development of its upper reaches. The third temperature regime was that of the natural river. The results indicated that hydroelectrical development of the Alta may lead to an earlier hatch of the salmon embryos in the river. Incubation time, and perhaps also a "trigger" such as rising temperature, may be more important than the heat sum (degree-days) of the incubation period in determining the exact timing of the hatch.

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