A southern sunfish (Mola alexandrini) found dead off the coast of Faial Island in the Azores has broken the record for the world’s heaviest bony fish – though there are boneless fish that weigh more

Life 14 October 2022

The record-breaking sunfish

AtlanticNaturalist.org

A dead southern sunfish (Mola alexandrini) discovered near the Azores in the Atlantic has taken the record for the world’s heaviest bony fish, weighing in at 2744 kilograms.

While there are heavier fish without bones, like the cartilage-filled whale shark (Rhincodon typus) which can weigh more than 20 tonnes, the previous record holder for the world’s heaviest bony fish was also a southern sunfish, found in Kamogawa in Japan in 1996, which weighed 2300 kilograms and was 272-centimetres long.

In December 2021, José Nuno Gomes-Pereira at the Atlantic Naturalist Association in Portugal and his colleagues found a large, dead sunfish floating off the coast of Faial Island. Gomes-Pereira and his team managed to pull the carcass to shore to weigh, measure and sample DNA from the fish.

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Using a crane, they weighed it at 2744 kilograms – more than 400 kilograms heavier than the previous heaviest – and measuring 325 cm in length.

While they don’t know what killed the fish, they found a large semi-cylindrical depression near its head marked with red paint, typically seen on the keel of boats. It isn’t clear, however, whether this mark happened before or after the fish died.

Journal reference: Journal of Fish Biology, DOI: 10.1111/jfb.15244

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