Climate Change

Global warming pushes marine fish to polar waters: Study

It remains to be seen how foodwebs and ecosystems will be affected by fish migration

By Arya Rohini
Published: Wednesday 31 May 2023

With vivid coral reefs and sizable concentrations of tuna, sea turtles and other species, the tropical oceans are recognised for their rich marine biodiversity. It has long been believed that the diversity of marine organisms gradually drops as we move poleward.

However, a recent study noted global warming to have pushed fish populations towards colder waters in the north and south poles.

Over the last century, global warming has substantially affected marine ecosystems, with fish species vanishing altogether from some locations, noted the research published in journal Global Change Biology on May 30, 2023.

Also read: Odisha’s fish stocks are depleting, courtesy warming seas; here’s how

Researchers from the University of Glasgow analysed global data and demonstrated how fish populations across the planet’s oceans are responding to rising sea temperatures. They examined data on 115 species spanning all major oceanic regions.

The surrounding water’s temperature affects marine organisms’ vital functions, such as metabolism, growth and reproduction. Furthermore, these organisms often have a thin liveable temperature range; they are intolerant to even little variations in the water. As a result, marine life responds seven times faster to a warming environment than terrestrial animals.

In certain circumstances, marine fish might be able to modify their biology and adapt to warmer environments. However, shifting the geographic range may be the only way to deal with the crisis in many instances.

“Rate of warming in some regions may be too fast for fish to adapt, so relocating may be their best coping strategy. At the same time, we see that their ability to do so is also impacted by other factors, such as fishing, with commercially exploited species moving more slowly,” Carolin Dahms, lead author of the study, said in a press release.

The researchers raised concerns over the potential impacts of such migrations on the ecosystem. Down the road, there might be severe repercussions if these species’ prey doesn’t follow them or they start to cause an invasive disturbance in their new habitat, they warned.

“While relocation to cooler water may allow these species to persist in the short-term, it remains to be seen how foodwebs and ecosystems will be affected by these changes,” said Shaun Killen, senior author of the study.

The researchers noted that our capacity to anticipate fish relocations would be crucial to safeguarding the world’s ecosystems and preserving food security as the impacts of global warming on marine ecosystems are expected to worsen.

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