Atlantic Salmon Acclimatise Well to Warmer Water Temperature
The offspring of salmon populations which have grown up in cold waters seem to be able to acclimatise to warm waters as well. An international research group discovered that salmon populations from northern Norway can live also in 20 °C water. The results were published in the esteemed Nature Communications scientific journal.
Researcher of Animal Physiology Katja Anttila.
The salmon’s ability to acclimatise can help fish especially from colder regions to respond to climate change in the future. An international research group discovered that northern fish have retained their ability to endure higher temperatures even though they have not experienced warmer waters in decades.
The group researched how the Atlantic salmon can adjust to climate change. The researchers used salmon from one of the most northern salmon rivers in Norway, the Alta River, where the water temperature has not risen above 18°C for the past 30 years.
The fish populations from the colder waters were compared with salmon from the Dordogne River in France. The water temperature in the Dordogne rises above 20°C each summer.
The Researchers Were Surprised about the Salmon’s Tolerance to Warmer Temperatures
The researchers raised the eggs and the larvae of the salmon populations from Norway and France in two different temperatures: 12°C and 20°C. Afterwards, the researchers measured the salmon’s cardiac responses in different temperatures. Earlier studies show that the cardiac functions limit the temperature tolerance of many fish species.
There were surprisingly few differences between the salmon populations even though they are genetically very different.
– Unlike we expected, the Alta salmon had nearly same capability to respond to higher temperatures as the Dordogne salmon, even though they have not experienced warm temperatures in decades, says Researcher Katja Anttila from the Department of Biology of the University of Turku.
Both populations had remarkable ability to acclimatise to a rise in temperatures. Fish from both populations, which grew up in 12°C water, had arrhythmia when the water temperature rose to 21–23°C. The salmon that grew up in 20°C experienced similar symptoms only when the temperature rose to 27.5°C.
– 8°C rise in the environmental temperature raised the salmon’s tolerance with no less than 6°C. It is quite remarkable when considering that salmonoids have a rather limited ability for acclimatisation as far as we know, says Anttila.
Only minor population differences were found in local adaptation. The Dordogne salmon had a slightly more rapid pulse in higher temperatures and could stand slightly warmer waters before experiencing cardiac collapse than the Alta salmon.
The research was funded by the Academy of Finland, among others, and it was carried out in cooperation with the University of Oslo and the University of British Columbia in Vancouver.
More information:
>>The research article in the Nature Communications journal
Text: Hannu Aaltonen
Translation: Mari Ratia