By Nneka Nwogwugwu
A study published in the Proceedings of the National Academy of Sciences has revealed that fleets of fish and other swimmers are gradually shifting rapidly to more temperate waters in Cuba, which could devastate the coral ecosystems they leave behind.
The Research published on Monday finds that the total number of open-water species declined by about half in the 40 years up to 2010 in tropical marine zones worldwide. During that time, sea surface temperatures in the tropics rose nearly 0.2℃.
While Cuba’s marine life has suffered from overfishing and pollution, there is mounting evidence that the warming of waters due to climate change may be taking a large toll as well — both off the island’s coast and globally.
“Climate change is already impacting marine species diversity distribution,” with changes being more dramatic in the Northern Hemisphere where waters have warmed faster, said study co-author Chhaya Chaudhary, a biogeographer at Goethe University.
While past studies have shown that ocean warming is driving some species to migrate to cooler waters, the new study attempts to gauge that impact more broadly — analyzing data on 48,661 marine species including fish, mollusks, birds and corals since 1955.
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The number of species attached to the seafloor remained somewhat stable in the tropics between the 1970s and 2010, according to the study. Some were also found beyond the tropics, suggesting they had expanded their ranges. In other words, scientists say, species that can move are moving.
“In geological history, this has occurred in the blink of an eye,” said Sebastian Ferse, an ecologist at the Leibniz Centre for Tropical Marine Research who was not involved with the study. “To see such changes occurring so rapidly is something quite alarming.”
For fixed species like corals, moving is not an option.
“One of the big questions is ‘Will coral reefs as ecosystems and corals as species be able to move north or south enough fast enough to adjust to a changing climate?’” Ferse said.
Such changes “can have a really huge impact on some of the most vulnerable human communities around the planet,” said Stuart Pimm, a conservation scientist at Duke University not involved in the study.
For Cuba, such an impact could unravel the island nation’s efforts to manage its underwater gardens although its corals have been less stressed by coastal development and pollution than corals elsewhere. They are considered more resilient to ocean warming.
Naturenews reports that Cuba opened its first coral reef nursery four years ago to research which species coped best with warming and eventually to repopulate depleted reefs. The country is also restoring coastal mangroves, which serve as fish nurseries and shelter.
