October 29, 2020 — An international team of scientists has found leaving more big fish in the sea reduces the amount of carbon dioxide (CO2) released into the Earth’s atmosphere.
When a fish dies in the ocean it sinks to the depths, sequestrating all the carbon it contains with it. This is a form of ‘blue carbon’—carbon captured and stored by the world’s ocean and coastal ecosystems.
“But when a fish is caught, the carbon it contains is partly emitted into the atmosphere as CO2 a few days or weeks after,” said Gaël Mariani, a Ph.D. student at the University of Montpellier in France.
Mr Mariani led a world-first study showing how ocean fisheries have released at least 730 million metric tons of CO2 into the atmosphere since 1950. An estimated 20.4 metric tons of CO2 was emitted in 2014—equivalent to the annual emissions of 4.5 million cars.