Timing of Spawning in Norwegian Atlantic Salmon (Salmo salar)

1988 ◽  
Vol 45 (5) ◽  
pp. 845-849 ◽  
Author(s):  
Tor G. Heggberget
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Temperature Regime ◽  
Stream Flow ◽  
Optimal Time ◽  
Degree Days ◽  
Egg Incubation ◽  
Atlantic Salmon Salmo Salar ◽  
Spawning Time ◽  
Timing Of Spawning

A hypothesis that thermal regime regulates the timing of spawning in Atlantic salmon (Salmo salar) was analysed by correlating time of commencement and peak of spawning in 16 Norwegian streams with temperature, latitude, and stream flow. Only temperature during incubation of the eggs proved to have any statistically significant effect. Since the duration of egg incubation is known to depend on temperature regime (i.e. on degree-days), a similar linking of spawning time to stream temperature allows spawning to occur at a time which will result in hatching of eggs at a specific and presumably optimal time for survival of fry.

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.

Different Adaptation Strategies of Atlantic Salmon (Salmo salar) Populations to Extreme Climates with Special Reference to some Cold Norwegian Rivers

1986 ◽  
Vol 43 (5) ◽  
pp. 980-984 ◽  
Author(s):  
Arne Johan Jensen ◽  
Bjørn Ove Johnsen
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Temperature Regime ◽  
Growth Rates ◽  
Temperature Limit ◽  
Fixed Temperature ◽  
Sea Temperature ◽  
Atlantic Salmon Salmo Salar ◽  
Lower Temperature Limit ◽  
Lower Temperature

Some of the salmon rivers on the western and northern coasts of Norway are very cold, and the sea temperature outside these rivers is almost always higher than that in the river. Growth rates of Atlantic salmon (Salmo salar) parr and smolt ages and sizes have been examined in three such cold rivers. We found indications that the lower temperature limit for growth of Atlantic salmon is not a fixed temperature, but varies from population to population according to the temperature regime of their environment. Smolts are small, with average sizes of 12–13 cm total length. Females dominated in number among the smolts, but the dominance was less pronounced than in most other rivers. Strategies used by Norwegian salmon in cold rivers are therefore different from those employed by salmon in the northern extremes of the salmon's range in Canada.

Growth of Atlantic salmon (Salmo salar L.) in a variable diel temperature regime

Aquaculture ◽  
1990 ◽  
Vol 90 (3-4) ◽  
pp. 261-266 ◽  
Author(s):  
Ole Kristian Berg ◽  
Bengt Finstad ◽  
Gjert Grande ◽  
Einar Wathne
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Temperature Regime ◽  
Atlantic Salmon Salmo Salar

Responses of Atlantic salmon alevins to temperature gradients

1979 ◽  
Vol 57 (7) ◽  
pp. 1424-1430 ◽  
Author(s):  
R. H. Peterson ◽  
J. L. Metcalfe
Keyword(s):  
Locomotor Activity ◽  
Temperature Gradient ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Temperature Gradients ◽  
Degree Days ◽  
Temperature Selection ◽  
Atlantic Salmon Salmo Salar ◽  
Distributional Change

Newly hatched Atlantic salmon (Salmo salar) alevins aggregated in the lowest temperature available in a temperature gradient, possibly because of lower levels of locomotor activity at lower temperatures. At approximately 250 degree-days after hatching, alevins demonstrated a temperature selection capability and no longer aggregated in the lowest temperature. Possible mechanisms underlying the observed distributional change in a temperature gradient are discussed.

Difficulties in Aging Atlantic Salmon (Salmo salar) and Brown Trout (Salmo trutta) from Cold Rivers Due to Lack of Scales as Yearlings

1982 ◽  
Vol 39 (2) ◽  
pp. 321-325 ◽  
Author(s):  
Arne Johan Jensen ◽  
Bjørn Ove Johnsen
Keyword(s):  
Atlantic Salmon ◽  
Water Temperature ◽  
Salmo Salar ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Age Determination ◽  
Considerable Proportion ◽  
Degree Days ◽  
Atlantic Salmon Salmo Salar ◽  
Brown Trout Salmo Trutta

Scales in Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) from two cold Norwegian rivers first appeared when the salmon were 33–34 mm long (total length) and the trout were 35–38 mm long. A considerable proportion of the yearlings did not form scales in years with a low water temperature (less than 1000–1100 degree-days from May to October); these individuals lacked the first annulus in the scales. Scales with five circuli or more seldom occurred. The number of days per year with a water temperature above 6.5 °C was better correlated to the formation of scales in Atlantic salmon than the degree-days. In years when the water temperature exceeded 6.5 °C for more than 70–80 days, only minor errors arose in age determination of the salmon; when the temperature exceeded 6.5 °C for less than 70–80 days, some individuals lacked the first annulus in their scales.Key words: Atlantic salmon, brown trout, age determination, temperature, scale formation

Embryo Movements of Atlantic Salmon (Salmo salar) as Influenced by pH, Temperature, and State of Development

1983 ◽  
Vol 40 (6) ◽  
pp. 777-782 ◽  
Author(s):  
R. H. Peterson ◽  
D. J. Martin-Robichaud
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Subsequent Development ◽  
Developmental State ◽  
Low Ph ◽  
Temperature Sensitive ◽  
Degree Days ◽  
Pectoral Fin ◽  
Atlantic Salmon Salmo Salar ◽  
Trunk Movements

Two types of embryo movements of Atlantic salmon (Salmo salar), pectoral fin flutter and trunk movements, were measured as a function of incubation temperature, pH, and developmental state. Trunk movements began at 200 degree-days, initially at highest frequency. The frequency decreased throughout subsequent development and then increased slightly just before hatching. Movements were much more stereotyped in the earliest stages of development than just prior to hatching. Frequencies at 200 degree-days were insensitive to temperature and pH. Frequencies just prior to hatching were very temperature sensitive (Q10 of 13) and were decreased at low pH. This decreased frequency may be related to documented effects of temperature and low pH on hatching. Pectoral fin movements were temperature sensitive (Q10 of 2) and pH insensitive. These movements were initiated at 350 degree-days of development and attained maximal frequency at 400 degree-days.

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