Impact of oceans warming on fish

Context

The Intergovernmental Panel on Climate Change (IPCC) report has warned that ocean warming will continue over the 21st century and is likely to continue until at least the year 2300 even if we minimise carbon emissions.

What will be the key impacts?

• Warming oceans can cause stress, decrease the range, increase diseases and even wipe out many commonly eaten fish.
• The future ocean warming and acidification may drag down the commercial Arctic cod fishery by 2100.
• Fish will start migrate poleward or to deeper waters to stay in their ideal temperature range.
• The total number of open-water species in tropical marine zones declined by about half in the 40 years up to 2010.
• Studies suggest fish like sardines, pilchards and herring will become smaller in size and not be able to move to better environments.
• With sea temperatures rising faster than ever, fish will very quickly get left behind in evolutionary terms and struggle to survive. This has serious implications for all fish and our food security, as many of the species we eat could become increasingly scarce or even non-existent in decades to come.

Which fish will survive climate change?

• Studies suggest that the three-spine stickleback fish can adapt rapidly to changes.
• The modern version of Darwin’s idea of evolution by natural selection posits that organisms with genes that favour survival and reproduction will tend to leave more offspring than their peers, causing the genes to increase in frequency over generations.