A rare species of marlin has been discovered off the coast of Bermuda in what is believed to be a first-of-its-kind catch.

A juvenile sample of the roundscale spearfish was caught by scientists conducting a survey of marine life in the Atlantic.

Another trawl by the same team netted a roundscale spearfish egg in an early stage of fertilisation.

According to a report in the Miami Herald, the catches are the first documented recordings of an egg and a juvenile of the species.

The team of scientists were aboard the German research vessel Walther Herwig III conducting studies into young eels to the south of the island.

They used a fine-mesh trawling net to collect samples at dozens of sites before putting their catch under the microscope.

Researchers tested the DNA of both samples and realised they had caught an elusive species.

The infant roundscale spearfish measured less than two inches and was believed to be only a few weeks old.

The roundscale spearfish, or Tetrapturus georgii, is a poorly known species found in the Atlantic.

It is so rarely seen and hard to identify that scientists doubted its existence for decades, with much of its lifestyle remaining a mystery.