The future of cod fishing seems uncertain, as the warming of the oceans kills young fish and increases the population in ever smaller areas, according to a new study.
It is expected that up to 60 percent less will be in the key fishing areas around Iceland and Norway if the greenhouse gas emissions continue at the current levels, a team of researchers at the Alfred Wegener Institute in Bremerhaven, Germany, suggested.
As these cold-loving fish are pushed further north, they will also be affected by the oceans that turn into acid because the excess CO2 from the atmosphere dissolves in the water, wrote in their published journals Scientific advances.
Following UN warnings that world leaders need to step up their climate commitments, scientists say recent research says only the strictest global warming targets will keep cod stocks stable.
Until recently, cod stocks in the North Sea have been threatened by the fact that after four decades the number has fallen by more than 80%.
Efforts to tackle overfishing have since led to a gradual recovery.
Last year, the fish was designated as a sustainable Austrian Marine Board for the first time in 20 years.
However, climate change is now another major challenge for global fish stocks, and hundreds of species are expected to be forced north to find cooler waters.
Cod especially needs to spawn at temperatures approaching frost to make their eggs develop properly.
Combining their expertise in fish development and climate models the scientists of this latest study predicted survival rate for cod.
"They show that conditions for young Atlantic cod will particularly worsen in the North Atlantic near the end of this century for the Business as-usual scenario," said lead author Flemming Dahlke. "In the regions around Iceland and Norway, as much as 60 percent of the larvae of hake will be hatched from eggs."
Fish are particularly sensitive at these early stages and even small temperature changes can cause eggs to die or produce deformations in larvae.
Polar whiting is particularly sensitive to temperature changes. They live in the extreme north and therefore will not migrate anywhere like the warm oceans. Meanwhile, their family cousins may not be able to reach north from the Arctic Circle until 2100.
Despite their grim predictions, scientists have found that if global warming were limited to 1.5 ° C above pre-industrial levels, an ambitious target set by the Paris Climate Agreement, most of the harmful effects on cod could be avoided.