Jump in jellyfish numbers 'must not be ignored'

Growing number of the very poisonous box jellyfish are being spotted off the Welsh coast. Credit: Marine Conservation Society

The UK's leading marine charity says 2015 has been another bumper year for jellyfish sightings in UK seas.

The Marine Conservation Society says the massive barrel jellyfish have appeared in record numbers in Wales for a second consecutive year.

The marine charity says the rise of jellyfish in UK seas can no longer be ignored, and that more dedicated research and monitoring is needed to understand these apparent increases and what they mean for the state of our seas.

Growing numbers of the 'compass' jellyfish are being observed in South West Wales. Credit: Marine Conservation Society

The Marine Conservation Society started its jellyfish survey in 2003, using data collected from thousands of members of the public in Wales and the rest of the UK.>Figures obtained so far this year suggest 2015 will be a record breaking year for the number of reported jellyfish sightings in Wales.>The charity says that highly poisonous barrel jellyfish normally make up 10% of its annual reports, but last year they made up 40%. So far in 2015, a whopping 75% of records have involved barrel jellyfish sightings.

Moon jellyfish started multiplying noticeably in May, and have forced closure of some power stations. Credit: Marine Conservation Society

As well as proliferating populations of barrel jellyfish, other types have been multiplying including the moon, compass and blue jellyfish, while sightings of the lion's mane jellyfish were reported all over Wales, Scotland and Northern Ireland by July.

The Lion's Mane jellyfish only started to appear in May, by July were reported all around Scotland, Northern Ireland and Wales. Credit: Marine Conservation Society

Marine researchers are concerned not only about the implications this may have for changes in our seas, but also the impact on industry.

For example:

  • Moon jellyfish blooms have forced the closure of UK nuclear power stations, leading to the industry investing in remote sensing mechanisms to detect increases in jellyfish near power plants.

  • Large blooms of mauve stinger jellyfish have wiped out salmon stocks in fish farms across the UK.

The Marine Conservation Society say it is important vital funding is given to investigate just why these jumps in jellyfish numbers are happening.