LONDON/HONG KONG, July 6 (Xinhua): Up to 60 per cent of fish species around the globe would be susceptible to warming waters by 2100, a British weekly magazine has reported.
In a worst-case scenario of global warming when the temperature increases by 5 degrees Celsius, oceans would be too hot for 60 per cent of fish species to live in, New Scientist cited a study as reporting last week.
"Even if humanity meets the Paris deal's tough goal of holding warming to 1.5 degrees Celsius, it would be too for 10 percent of fish," the British media reported.
The research analysed existing scientific literature on the heat tolerance of 694 species of freshwater and marine fish spices, finding that embryos and spawning adults are more vulnerable to warming oceans due to their greater oxygen needs, said the report.
But to really understand how warmer waters will impact species, the researchers argued that it’s essential to look at the most vulnerable stages in a fish’s life cycle — those that are critical to reproduction and species survival.
In nearly all cases, fish embryos and spawners — female and male fish that are preparing to produce eggs and sperm — are far more vulnerable to abnormally warm water temperatures than adults and larvae, the researchers found.
Today, an estimated 3 billion people rely on fish and seafood as their primary source of protein.
To survive, many species would be forced to evolve to cope with warmer temperatures or to move in search of cooler waters, the authors said. But given the speed with which human activity is warming the planet, many species may not be able to adapt fast enough to survive.
As the planet heats up, several other recent studies have shown how oceans in particular have borne the brunt of the warming.
It’s “virtually certain” that the world’s oceans have warmed nonstop since 1970 and have absorbed 90 percent of the planet’s excess heat, according to a landmark report last fall from the United Nation’s Intergovernmental Panel on Climate Change. - Xinhua
news source : https://www.thestar.com.my/aseanplus/aseanplus-news/2020/07/06/global-wa...