A lionfish swimming on its own across a coral reef.

Lionfish are usually found on tropical reefs in the Pacific Ocean © Vitaliy6447 / Shutterstock

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Lionfish caught off the coast of Dorset could be a record for the UK

A lionfish has reportedly been caught off the coast of Dorset, UK. Normally native to the tropical reefs of the Pacific Ocean, it could represent the first-ever sighting of the fish in UK waters.

The origin of the fish is unclear, so scientists at the Museum urge anyone who knows more about it or its location to get in touch.

An invasive species of fish which could pose a threat to British wildlife has reportedly been captured off the south coast of England.

Earlier this month, 39-year-old Arfon Summers is said to have caught a lionfish on Chesil Beach, Dorset. If verified, the venomous fish would be a first in the UK and could pose a threat to native wildlife.

Dr Oliver Crimmen, the Senior Curator of Fish at the Museum, says the find is important and needs to be verified.

'It is important to establish the circumstances of the catch, and to obtain the body if possible to establish which species of lionfish it is,' he says. 'If it arrived in the UK by itself from more southerly latitudes, this could be bad news since it is such a potentially invasive species.'

Plenty more lionfish in the sea?

Lionfish are a group of colourful striped fish whose body is covered in venomous spines, which can cause severe pain if touched.

Native to the Pacific Ocean, they have become an invasive species across large parts of the world, especially in the Caribbean and Mediterranean. They have successfully expanded their distribution thanks to their tolerance for a range of temperatures, as well as their high fertility and potent venom.

Their spread is believed to result in part from the aquarium trade, with owners having intentionally or inadvertently let their fish escape into the ocean. The fish caught off Chesil Beach may have itself been released from a private collection in the UK and then been re-caught. 

However, the presence in the Mediterranean makes it possible that the fish may have arrived in UK waters naturally.

'Anything caught in the Mediterranean can be found as a vagrant species in the UK,' Oliver says. 'The first instances of warm water fish from more southerly latitudes being found in the UK are a subject of great interest, as they may represent populations moving northward in response to higher coastal water temperatures. 

Fish out of water

The next step in investigating the significance of this find is to have the catch verified and examined.

In the UK, catches are verified by the British Record Fish Committee, of which Oliver is a scientific member. To be verified, a variety of evidence, including witness statements, is needed for the organisation to certify a British record.

The committee has been involved in a number of submissions of vagrant fish from Chesil Beach in recent years. This includes the first British record of a pompano dolphinfish in 2017, while the derbio and the saury, two extremely rare fish, were caught there in 2018.

If confirmed, then the lionfish would be a British record and scientific first for the UK in its own right. The opportunity to examine the captured lionfish could offer valuable information about where it came from, and the potential for more of its species to come in future.

'If someone's got the lionfish specimen in a freezer, we would love to see it,' Oliver says. 'The arrival of a species with such invasive potential as a lionfish, however, could represent a future threat to UK marine ecosystems.'