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MCS Jellyfish Survey

Lions mane jellyfish - (C) Ian StewartHelp us learn more about what is happening to jellyfish populations in UK seas!

You can help - MCS would like your help recording jellyfish strandings on UK beaches and jellyfish swarms in our seas. If you visit the seaside, regularly walk along beaches, are a Beachwatch volunteer, dive or sail, you can help!

Download your free Jellyfish Identification Guide and report your sightings here.

Jellyfish Identification

Identification of live jellyfish is usually easy but once they've washed up on the beach it can become more difficult. Please do not guess if you are not really sure, just record the jellyfish as 'Unidentified' and describe it on the form. If possible, take photos of the jellyfish bell and manubrium (mouth and arms, underside and centre of bell) to help with identification later and send them to us at

Health and Safety

Some jellyfish can sting, so:

  • Never touch jellyfish with bare hands

  • Always use a stick or wear arm length rubber gloves if you need to turn them over for identification

  • Beware of the stinging tentacles and keep your face and any exposed skin well clear

  • Seek medical attention in the case of a severe sting

Jellyfish and leatherbacks

Turtle eating  jellyfish - (C) SeaPics

Little is known about jellyfish in UK waters, but we do know that they are the staple diet of the threatened leatherback turtle. These spectacular reptiles are seasonal visitors to UK seas, migrating from their tropical nesting beaches, and analyses of stomach contents of dead leatherbacks stranded on UK shores have revealed that they feed on several species of British jellyfish. By comparing the distribution of jellyfish with environmental factors such as sea temperature, plankton production and current flow, we hope to understand what influences the seasonal distribution of jellyfish in UK waters.

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