Wildlife & Nature to See in August : Jellyfish

Wildlife to See in August : Jellyfish

As the school holidays begin, the Marine Conservation Society (MCS) is again calling on British seaside visitors to take part in the national MCS Jellyfish Survey and report their sightings of these bizarre but fascinating creatures. Large jellyfish blooms have already been reported washing up on beaches in England, Scotland and Wales, and as the UK’s seas warm up during the summer, more jellyfish blooms are expected.

© Calum Duncan/MCS: Lion's Mane Jellyfish

© Calum Duncan/MCS: Lion’s Mane Jellyfish

“This year’s jellyfish season started in April in the Irish Sea, when barrel jellyfish were reported off the Welsh coast. In May we started to receive reports of big blooms of the harmless moon jellyfish from around the UK, and then through June and July, large numbers of the beautiful blue and compass jellyfish also started to wash up on our beaches,” said Peter Richardson, MCS Biodiversity Programme Manager, “Blooms of the stinging Lion’s Mane jellyfish have been recorded in the Irish Sea as well as on Scotland’s east coast, and a potentially dangerous Portuguese Man Of War was recorded near Land’s End in Cornwall in mid-July. As ever, we are encouraging holidaymakers to take part in our national jellyfish survey, but the key message is look, don’t touch!”

The Link Between Jellyfish and Turtles

The MCS Jellyfish Survey aims to uncover the little-known habits of British jellyfish, as part of a wider programme to find out more about critically endangered leatherback turtles that migrate thousands of miles to UK waters to feed on their favourite jellyfish prey each summer. By mapping where and when the jellyfish are seen, MCS hopes to understand more about leatherback turtles while they visit in UK seas.

© Tim Fonshawe: (Dead) Barrel Jellyfish

© Tim Fonshawe: (Dead) Barrel Jellyfish

“Our survey has already recorded some unusual jellyfish events. For example, last summer we received many reports of the usually rare Portuguese Man of War washing up on beaches in Devon and Cornwall. Then in November our volunteers recorded a vast and unseasonal bloom of the Mauve Stinger jellyfish move into our waters along Britain’s north west coast,” said Peter Richardson, “Mauve Stingers can sting quite badly, and have wreaked havoc at holiday destinations throughout the Mediterranean. Last years’ Mauve Stinger bloom stretched from Northern Ireland to the Shetland Islands and severely affected salmon farms off Northern Ireland and the west coast of Scotland. We are not sure if the Mauve Stinger bloom was a one-off event, but scientists are predicting that climate change will result in more jellyfish in UK waters and the MCS jellyfish survey aims to record these unusual blooms if they happen again.”

MCS is interested in the six larger jellyfish and two jellyfish-like species likely to be encountered around the UK coast that are known to be leatherback prey. This year British beach-goers and sea-users are encouraged to record their jellyfish encounters at www.mcsuk.org, where a free MCS jellyfish identification guide can also be downloaded. Paper copies of the ID guide and forms are also available on request, however MCS advises the public to take care during the survey.

Over 5,000 jellyfish encounters have been reported since the MCS Survey was launched in 2003. The survey data will be fully analysed in collaboration with the University of Exeter’s Centre for Ecology & Conservation, but initial analysis of these public reports is already showing interesting differences in the distribution of the larger jellyfish species around Britain (as shown in table below).

N.B. Article originally published in August 2008 reflected in the data shown below.

Jellyfish species Distribution This year’s records
Barrel (harmless) Blooms largely restricted to the Firth of Clyde, Solway Firth and Irish Sea, but strays are recorded further south. Large blooms off Wales in April.
Lion’s Mane(powerful sting) Northern seas, not usually recorded south of the Irish Sea or Northumberland.  Reported in Irish Sea from May onwards, off the east coast of Scotland in June, and one as far south as Bacton, Norfolk in mid-July.
Blue (mild sting) Entire UK coast.  Started to bloom around the UK coast in June, continuing through July.
Compass (mild sting) Entire UK coast. Started to bloom around the UK coast in June, continuing through July.
Moon (harmless) Entire UK coast. Started to bloom around the UK coast in May, continuing through July.
Mauve stinger(powerful sting)  Occasionally reported from the Channel Islands & SW England, large unseasonal bloom of western UK in 2007.  No UK records so far, although large blooms reported in parts of the Mediterranean.
Portuguese Man Of War (dangerous sting) Occasionally recorded from South West coast – in summer 2007 many were recorded there. One record of a small specimen found at Sennen beach, Cornwall on the 11th July.


How You Can Help

Taking part in the jellyfish survey is easy! The full-colour MCS jellyfish photo-ID guide can be downloaded from www.mcsuk.org where jellyfish encounters can be reported online. Alternatively, if beach goers want a paper copy of the ID guide and recording forms, they are available on request from the MCS office on 01989 566017 or info@mcsuk.org.

The Marine Conservation Society’s website has lots of information about marine life off the coast of Britain and is well worth a look.