A HUGE increase in the number of jellyfish around the coast of South East Cornwall could indicate fundamental changes in the condition of our seas, says the Marine Conservation Society (MCS).

Further groups (or ‘smacks’) of barrel jellyfish have been sighted in and around Looe this week. The large, white creatures, sometimes known as ‘dustbin jellyfish’ owing to their shape and size, have been troublesome to local fishermen, who have had to pull them out of their nets by the hundreds.

Other species spotted around the South West in greater number this year include the potentially dangerous Portuguese Man O’War.

MCS is calling for more monitoring of the rise in jellyfish numbers – and dedicated research to help understand the reasons behind it.

Barrel jellyfish usually make up 10 per cent of the society’s annual sightings – but so far this year, account for 75 per cent of the reports made.

‘We know that our seas are changing through climate change, resulting in rising sea temperatures and increased ocean acidification, and we know our seas are also heavily fished,’ says biodiversity and fisheries programme manager for the MCS, Dr Peter Richardson.

‘At the same time we seem to be witnessing increases in jellyfish around the UK. Is this a coincidence – or are the jellyfish telling us something about fundamental changes in the condition of our seas?’