© The Independent, UK
Last December British Fish and Chips was going to become Squid and Chips thanks to Climate Change. This year, cod will become anchovies. Battered anchovie anyone? British Fish and chips have been dying for a decade.

Now, apparently, fish are shrinking, thanks to falling oxygen levels in the seas:
By 2050, the size of fish could shrink by 10 - 20 per cent, Dr William Cheung, a marine ecologist at the University of British Columbia, Canada, forecast.

Dr Cheung, who gave a keynote address at the 50th Anniversary Symposium of the Fisheries Society of the British Isles at Exeter University this week, said some fish in the North Sea, including haddock, were already getting smaller.
Some might say the shrinking Haddock might have more to do with over-fishing.
He predicted the trend would continue with common species such as cod shrinking by up to a fifth within our lifetime.
Get ready for "child's portions" of fish and chips. No really, that's the headline, not the punchline.

Climate change will extinguish Life on Earth but if that doesn't scare you, let me tell you about your shrinking food. Kiddie meals are coming!
The marine ecologist said fish are shrinking because climate change is reducing the oxygen in the seas available for fish to breath.
The marine ecologist went on to say that because oceans are warming, fish that swim around Portugal and Spain will call the UK home.

Right now the ocean around the UK is 17C — at least three degrees colder than the water off Portugal. The ARGO buoys estimate the ocean is warming at 0.005°C per year (plus or minus 0.5° C, don't laugh now.) So only 600 years to go at this rate, give or take 60,000 years.

How much is oxygen actually declining?
The rise in ocean temperature is reducing the oxygen in the waters for fish to breathe, while increasing fish's need for oxygen simultaneously. Fish are more easily 'short-of-breath' as they grow bigger.

As the temperature of the surface of the oceans increases, the water holds less oxygen for fish to breathe. This is exacerbated because, as the seas warm up, oxygen from the depths of the ocean does not mix with the surface water as readily. In addition, water does not circulate as swiftly, which means the deep ocean is not as well ventilated.
I'd like to see some measurements on those falling oxygen levels before I stock up on frozen codfish.

Dr Cheong seems to be mixing up atmospheric warming with ocean warming:
In the last few decades the surface oceans have warmed up by less than a degree celcius. Dr Cheung, a former lead author in the Working Group II of the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), projected that achieving the Paris Agreement of the 1.5 - 2.0 oC global warming targets will substantially reduce impacts. But if emissions are not reduced, there could be 3.5 - 4.0 oC warming, by the end of the century.
Extrapolated fish are coming your way.

"Oh My Cod" comes from Sophie Morris and The Sun.