Salmon May Adapt in the Face of Climate Change: Fish Adjust to Warm Waters

There's some good news when it comes to our supply of salmon. Scientists have found that populations of Atlantic salmon have a surprisingly good capacity to adjust to warmer temperatures, which they may just have to do in the face of climate change.

Climate change continues to affect oceans and rivers, warming temperatures. Understanding how fish adapt to these changes in therefore important when it comes to assessing how well populations might do in the future-especially for a commercially-important fish like salmon.

In order to learn a bit more about this species, the researchers examined wild salmon from two European rivers. More specifically, they compared a cold-water population from Norway's northern Alta River to a warm-water population from France's Dorgogne River. They hatched eggs from both populations in a lab and then raised the fry under varying temperatures.

So what did they find? It turns out that when reared in 12 C temperatures, salmon from both populations developed cardiac arrhythmias at 21 to 23 C, after a maximum heart rate of 150 beats per minute. Those raised at 20 C, though, developed cardiac arrhythmias at a surprising 27.5 C, after the heart reached 200 beats per minute. In other words, being raised in warmer waters meant that the fish could withstand warmer temperatures.

"The results are surprising," said Tony Farrell, one of the researchers, in a news release. "A fish faced with uncomfortably warm temperatures might relocate or even die if it is too extreme. Here we have evidence for warm acclimation of a commercially and culturally important fish species."

The findings reveal that salmon can adapt to warmer temperatures by simply being exposed to them as they're developing. This is good news for the species as waters continue to increase in temperature in the face of climate change.

The findings are published in the journal Nature Communications.