How fish keep their cool in warming oceans
AN international study of ocean warming suggests that some cold water species will continue to thrive by seeking refuge in cooler, deeper water.
Researchers from the UK, Japan, Australia, the US, Germany, Canada, South Africa and New Zealand analysed three million records of thousands of species from 200 ecological communities across the globe.
Reviewing data from 1985 to 2014, the team, led by Prof Michael Burrows of the Scottish Association for Marine Science (SAMS) in Oban, showed how subtle changes in the movement of species that prefer cold water or warm water, in response to rising temperatures, made a big impact on the global picture.
The findings, published in the journal Nature Climate Change, show how warm water species increase and cold water marine species become less successful as the global temperature rises.
However, the study also shows how some cold water species adapt.
While the global warming trend was widely seen, the North Atlantic showed the largest rise in average temperature during the time period.
But for fish communities in the Labrador Sea, where the temperature at 100m deep can be as much as five degrees Celsius cooler than the surface, moving deeper in the water column allowed the cold water species to remain successful.
The different responses of species to warming make predicting biodiversity redistribution and relative abundance a challenge, the report noted.
‘The composition of fish communities changed less than expected in regions with strong temperature depth gradients,’ it said, adding that in these communities, there is a ‘strong prognosis of resilience to climate change’.