British Marine Life Study Society 


Moon Jellyfish (Photograph by Noel Cornwall)

Moon Jellyfish in Shoreham Harbour
Photograph by Noel Cornwall

Common Moon Jellyfish

Five Species of British Jellyfish

Colonial Hydrozoans

Barrel Jellyfish

Compass Jellyfish

Lion's Mane Jellyfish

Sting of a Jellyfish

Treatment of Stings

International Conference

Jellyfish Blooms


by Jane Lilley

Moon Jellyfish
Photograph by David Hall

Common Jellyfish (also called Moon Jellyfish), Aurelia aurita, which do not sting humans. The threadlike tentacles around the edge of the bell can sting, and may occasionally catch small swimming animals for food, but their stings - like minute harpoons fired by springs - are not powerful enough to pierce our thick skin. They feed mostly by trapping microscopic plankton in a film of mucus which flows over the surface of the bell and is picked off as it reaches the edges by the thick mouth tentacles underneath. They swim by pulsing the bell, pushing themselves slowly forwards through the water.

Inside the top of the bell you can see four rounded pinkish masses, which are the gonads.


In October or November the jellyfish will breed, releasing tiny swimming embryos into the water, and the adults then probably die as the water gets colder. The embryos attach themselves to fixed structures, and it would be well worth looking for them on the piles of piers, although they are only 1 or 2 cm long. They look a bit like tiny sea anemones for a long time, and feed and grow like this for a year, hanging downwards from a support. In their second winter they lose their tentacles, and their bodies elongate and gradually divide crosswise into a stack of little discs. Eventually these break free one by one and swim away to grow into tiny jellyfish.

Although jellyfish can swim slowly, they are largely at the mercy of the tides and currents, and at times large numbers are concentrated into bays, and may be stranded on beaches. The most spectacular swarms are seen in late summer when they are at their largest.
May 1999
Moon Jellyfish, Aurelia aurita, swarming in hundreds (possibly totalling over a thousand) in Shoreham Harbour, Sussex. This jellyfish is common and widespread throughout the oceans of the world and is common all around the coast of Britain. It would not deserve a special comment if they had been recorded regularly at this location before - they had been for about 4 years, but not in so many numbers. The largest specimens reached 125 mm in diameter and the pink gonads were visible in some specimens. It seems a good year of all species of jellyfish around Britain with records of the venomous Lions' Mane Jellyfish, Cyanea capillata from Scotland in larger numbers this year.

The best viewing area is the piece of waste land opposite where the old Gas Works used to be and  to the east on the other side of the canal to where the new Natural Gas Power Station is being built.

Richard Huggett reports thousands from off Eastbourne, 20 miles to the east up the English Channel, so the swarms must occur all along the English Channel. It seems a good year (1999) of all species of jellyfish around Britain with records of the venomous Lions' Mane Jellyfish, Cyanea capillata from Scotland in larger numbers this year.

A raft of Moon Jellyfish (Photograph by Alisdair Gurney)By 25 July 1999, the jellyfish seemed to have disappeared in Shoreham Harbour.  AH.

On 14 July 1999, Averil Brond reported many Moon Jellyfish from the strandline Padstow (SW 9177), Cornwall. They were stranded from the last week in June 1999 to the second week in July. Around 22 July 1999 hundreds were stranded at Mother Ivey’s Bay (SW 8676) , reported by Mrs V C Tummon.
from Seaquest SW (Cornwall Wildlife Trust web pages).

Sting refs (link)
Notes (obscure refs)

August 2002 (beginning)
The large and dense mass of Moon Jellyfish in Loch Nevis (Scotland) was particularly outstanding. The enhanced photograph (right) gives some idea of the density. The congregation of jellyfish measured 12 metres by 3 metres and at least a metre thick.

Report and photograph by Alisdair Gurney

6 June 2004
An extraordinary raft of Moon Jellyfish, Aurelia aurita, was seen eight miles (13 km) off the coast of north-west Wales, off the Lleyn peninsula at the north of Cardigan Bay. The Moon Jellyfish had somehow contrived to wedge themselves together into a continuous raft of eight metres square, each of the tens of thousands of jellyfish about 10 cm in diameter, each wedged several deep in one large teeming mass, each jellyfish "pulsing down" in the glassy dead calm sea between two headlands. This unusual congregation has been reported once before in the enclosed Scottish Loch Nevis, but has not been recorded before in the open sea.

Report by Barry Pugh

Aggregations (Smacks, or drifts, or swarms etc.) of Jellyfish

The reason that they occur in aggregations is not intentional but purely a factor of their planktonic lifestyle.  Where feeding conditions are good the sessile asexual reproductive phase, the polyp will thrive, and all come to maturity at much the same time.  This may lead to an almost synchronous release of the young jellyfish or ephyrae.  If these find suitable food they will grow and all the youngsters from one area will drift around together as dictated by the currents and influenced by the winds.  The only way a jellyfish could "decide" where it was going would be by moving up or down in the water column and finding itself in a water body moving in a different direction.
  Doug Herdson

Moon Jellyfish (Photograph by Andy Horton)Douglas Herdson
Information Officer
National Marine Aquarium
Rope Walk
Plymouth  PL4 0LF

Telephone: (+44)01752 275216 / 01752 600301
Fax: (+44)01752 600593

Five Other British Jellyfish:
           by Andy Horton
Barrel Jellyfish  Rhizostoma   pulmo (Pic)
Lion’s Mane Jellyfish Cyanea capillata.
Compass Jellyfish (Pic) Chrysaora hysoscella
Mauve  Stinger  Pelagia noctiluca
Blue  Jellyfish Cyanea lamarcki

The last 4 species can sting humans.

Hansard Common Names

The Portuguese Man o'War, Physalia physalis, and the By-the-wind Sailor, Velella velella, (Pic) are two jellyfish-type animals found on south-western coasts of Britain in some years. They are, technically, colonial hydrozoans, Physalia is in the Order Siphonophora, Velella is in the Order Athecata; of the Class Hydrozoa.


23 February 2019

Portuguese Man o' War at Maenporth
Photograph by Austen Osborne

Colonies of juvenile Portuguese Man o' War, Physalia physalis, have been discovered at several locations between the tides on Cornish shores. The juveniles are attached like sea anemones and lack the long venomous tentacles of the adults. I bet they can still give off a painful sting though.

Report & Photographs by Heather Bullivant
on Cornish Rock Pools facebook
6 November 2011
Portuguese Man-o'-War, Physalia physalis, and Mauve Stingers, Pelagia noctiluca, as well as Goose Barnacles, Lepas anatifera, were discovered washed ashore at Kennack Sands, on the eastern shore of the Lizard Peninsula, south Cornwall.
Image by Kennack Diving

8 October 2011
I  found three Portuguese Man-o'-War, Physalia physalis, loads of By-the-Wind Sailors, Velella velella, Buoy Barnacles, Dosima fascicularis, and Goose Barnacles, Lepas anatifera, at Sennen Cove and Gwynver Beach, Cornwall.

Report by Jo on the Cornish Wildlife Yahoo Group
Image by Paul Semmens
BMLSS Strandline Page
BMLSS Barnacles

30 August 2008

Photograph by Chris English

Portuguese Man-o'-War, Physalia physalis, washed up on Pendine Sands in Carmarthenshire, south Wales.

Photograph and Report by Chris English

17 August 2008
Nine potentially Portuguese Man-o'-War, Physalia physalis, were washed up on the West Sussex coast. The creatures, which can give a nasty sting, were found on beaches at Bracklesham Bay, East Wittering, West Wittering and Selsey.

BBC News Report

11 August 2008
Three Portuguese Man-o'-War, Physalia physalis, were washed ashore on the Dorset coast, notably one at Kimmeridge Bay which was placed on display in the Marine Life Centre.

BBC News Report

4 August 2008
I discovered a Portuguese Man-o'-War, Physalia physalis, on Southsea seafront, Portsmouth, to the east of the pier. This particular one was transparent rather than the distinctive blue colour and was only identified by its shape and form. The sting on the palm of my hand was mild but persistent and still felt ten days afterwards.

Report by Adam McGonigle

Portuguese Man-o'-War are a jellyfish type type of colonial hydroid that are washed up on western shores and sometimes on the English Channel coast in small numbers in some (less than half) years.
A Portuguese Man-o'-War was also washed up at Smuggler's Cove, Holcombe, near Teignmouth, in south Devon.

12 October 2008
I  found a small Portuguese Man-o'-War, Physalia physalis,  washed up on Cape Cornwall, west Cornwall.

Report by Kurt Jackson
5 February 2008

Two Portuguese Man-o'-War, Physalia physalis, were both discovered on the same beach (Lohar, Waterville, Co. Kerry Ireland) but one was down at the low tide and the other was much higher up.  They were both about 10 cm long  The other one was deflated.

Report by Rosemary Hill
26 October 2000
Portuguese Man-o'-War, Physalia physalis, were discovered washed up on the Sussex coast at Brighton. This has happened before, but not in the last 20 years. About 50 were discovered, but there were likely to be more.
Report by Dr Gerald Legg, Booth Museum of Natural History, Brighton
Portuguese Man o'War  (Photograph by Dr Gerald Legg)
Portuguese Man o'War

circa 9 October 2000
A Portland fisherman, Derek Galpin, discovered Portuguese Men O' War washed up on Chesil Beach, Dorset.  I went along to have a look and found about half a dozen in Chesil cove.  Derek said he hasn't seen them since 1967 - I certainly haven't seen them here before
Peter Tinsley
Marine Awareness Officer
Dorset Wildlife Trust
By 24 October 2000, 140 Portuguese Men O' War were discovered on Dorset shores.

9 October 2000
We have had prevailing north-westerly winds, which have brought in lots of Portuguese Man-of-war.  I found 8 yesterday (Sunday) on Guernsey's west coast Cobo and Saline beaches. Tony Bougourd who found 3 on Perelle Beach on October 6 found another one yesterday. He spoke to a fisherman who said there were 'hundreds stranded on an off-shore spit' outside Perelle.  Cuttlefish bones have also started washing up on west coast beaches in large numbers.  This is normal for this time of year. The cuttlefish migrate from the Normandy bays and move North-West into deeper Channel water.

Richard Lord (Guernsey)
circa 9 October 2000
Portuguese Man O'War have been found at Swanpool and Maenporth near Falmouth, Watergate Bay and Mawganporth near Newquay, Marazion and Prussia Cove, all Cornish coasts, over a wide area from both the southern and northern coasts.

6 October 2000
Tony Bougourd found 3 Portuguese Man-of-War washed on Guernsey's West Coast Perelle beach, the same week as they were found in 1999.  Richard Lord (Guernsey)

Portuguese Man o'War
(Photograph by Jane Herbert, Editor of the Cornwall Wildlife Trust web site)

2 October 1999
A Portuguese Man o'War, Physalia physalis, was washed up on  Porthcothan Beach (SW 8572), Cornwall. This colonial hydrozoan (jellyfish-like invertebrate animal)  has a float bladder that was fully inflated and 22 cm in length. There were quite a thick bunch of stinging tentacles still attached, to a length of about 15 cm. It was washed in with the incoming tide after a period of strong winds. It was washed in with the incoming tide after a period of strong south-westerly winds.

As expected, several more Portuguese Men o'War were discovered, five on Porthcothan, two on Watergate Bay and a friend found five on Gwithian (Hayle) beaches, over the weekend. Some specimens were alive and have been placed in an aquarium for further study.

By Sunday night the tally had increased to 22  from Hayle up to Trevose Head.   The tentacles on the biggest were well over a metre long, possibly twice that length (had they been given the chance to extend fully).

Report by Nick Darke (Cornwall)
 Portuguese Men o'War were reported over a large area of southern Cornwall and the Isles of Scilly . Over 100 specimens have been reported and there were probably many more stranded in inaccessible coves.
Stella Turk (Cornish WWT)
Portuguese Men o'War: Further Information on the Cornwall Wildlife Trust site
Portuguese Men o'War: Further Information on the Australian Museum site

By-the-wind Sailors,Velella velella

Link for the Latest Reports

9 January 2005
A post storm check of Thurlestone (south Devon) beach for stranded cetaceans or oiled birds revealed my first ever UK sittings of by the Jack-by-the-Wind-Sailors, Velella velella, several hundred, some as just the chitinous float and sail.. I have never noticed them before in Britain but I saw millions on beaches in SW Corsica last May. No sign of the predatory Violet Sea Snails, Janthina sp., often associated with this creature.

18-25 September 2004
The massive stranding of By-the-wind Sailors, Velella velella, has now been established that it has stretched much further than just the Cornish coast and that the numbers were in billions. Reports of large numbers of large specimens and huge numbers occurred all along the Welsh coast as far north as Anglesey and almost certainly further north as well.

Velella on a Cornish beach in September 2004 (Photograph by Jonathan Smith)
First strandings on Velella on the sandy beach at Polzeath, Cornwall
Photograph by Jonathan Smith
First strandings on Velella on the sandy beach at Polzeath, Cornwall
Photograph by Jonathan Smith

Some Reports:

24 September 2004
Thousands of Velella were washed up at Woolacombe, north Devon in unprecedented numbers, estimated up to 200 a square metre!

Report by David Jenkins via Gavin Black
Devon Biodiversity Records Centre (DBRC)
on the Marine Wildlife of the North-east Atlantic Ocean Group

At Westwood Ho!, north Devon Velella are two or three inches (50 - 75 mm) thick on the shore.

c.18 September 2004
Several hundred By-the-wind Sailors arrived on the beach on the Isle of Islay, west Scotland. The flesh rotted away quite quickly.

Report by Malcolm Ogilvie on UK Wildlife Yahoo Group

16 September 2004
Velella were found on the shore between Newquay in Wales and Aberaeron with a  length of 60 mm +. There was one every three metres or so around the rocks at Cei Bach thinning out in the sand areas. All were strikingly large compared to those I have found before in south Wales and Cornwall before. All had soft tissue and colour but were dead and disintegrating.

Report by Ian Hughes on the
Marine Wildlife of the North-east Atlantic Ocean Group
Early September 2004
We found large amounts of Velella velella out off the Pembrokeshire coast back at the start of Septernber and the ensuing storms seem to have deposited many of them on our beaches in the west of Pembrokeshire (at least). Their small size make them easy to overlook at sea and also on dark sand but they are exquisite jewel like creatures.
Report by Fred Jacob on the
Marine Wildlife of the North-east Atlantic Ocean Group

21-23 September 2004

Velella on Constantine Bay beach, north Cornwall, (Photograph by Amanda Bertuchi)

Velella on Constantine Bay beach, north Cornwall
Photograph by Amanda Bertuchi

A huge mass stranding of By-the-wind Sailors,Velella velella, occurred all along the north Cornish coast from Sennen Cove (near land's End) up to Polzeath (near Padstow) and beyond. (As the gull flies this is a distance of 25+ miles and with all the coves and inlets the shoreline is over double this.) Coming in on the top of the tide, there were hundreds of millions* of them, all large, the largest I found was 85 mm, and all them were intact. Millions of Barnacles were washed up along the strandline.

(* Numbers not calculated. At Gwithian they formed a band 10 metres wide on the shore and stretching for over a mile. The above photograph understates the extent of the  stranding.)

The Buoy Barnacles, Lepas fascicularis,started coming in on the same tide as the Velella. I've seen with my own eyes on Porthcothan (SW 8572), Treyarnon and Constantine and Paul Gainey saw them on Gwithian, all in north Cornwall. I'd be very surprised if they weren't all the way up the coast and I'd number them in millions, all big. The Goose Barnacles, Lepas,are occurring in their usual quantity for this time of the year, if anything, less. To give you an idea, on my beach, Pothcothan, 25 acres at low tide: Velella approximately one million, Buoy Barnacles: 2000+, Goose Barnacle colonies: 7.
At least one Portuguese Man o'War, Physalia physalis, was also washed up and there were undoubtably more.

Report by Nick Darke via the Cornish Mailing List

The Buoy Barnacles were attached to floats that they had secreted that had a texture like that expanding foam.

Comment by Clare Mullen on the
Marine Wildlife of the North-east Atlantic Ocean Group

BMLSS Strandlining
BMLSS Barnacles

6 June 2003
Millions (literally) of By-the-Wind Sailors, Velella velella, (a jellyfish-like animal) are being washed up alive to perish on the shores of Cornwall, now reaching up the English Channel as far east as Polperro and Looe.  All are a similar very small size, around 15 mm in length, and still have fleshy body parts attached.

Report by Jon Makeham on the Cornish Mailing List
More Cornish Reports
Velella page
Velella Notes
MARLin Velella Web Page

4 June 2003
We have got loads of By-the-Wind Sailors, Velella velella, in the Fowey estuary, Cornwall, as far up as Wisemans reach. They are coming in by the bucket load. Lots were stranded on Readymoney beach and there were lots washing in the night. I haven't seen any Violet Sea Snails, but am going out on the water this morning so shall look out.

Report by Jane Smith on the Cornish Mailing List

4 June 2003
I was on Charmouth beach in Dorset doing a little fossil hunting and suddenly found myself lying (best way to find tiny crinoids etc) in a wreck of tiny jellyfish. They had a bizarre transparent float and were a vivid blue being only around 25 to 30 mm long. These are By-the-Wind Sailors, Velella velella.

Report by Dave Walters
28 May 2003
David Muirhead sailed through a large fleet of By-the-Wind Sailors, Velella velella, on the SE side of Fal Bay. He said they were being tossed around and he wondered if they could capsize.
Michael Ennis reported a number at Nansudwell, Cornwall.
Report by Stella Turk MBE on the Cornish Mailing List

26 May 2003
Hundreds of By-the-Wind Sailors seen approximately half a mile SE of Guernsey, Channel Islands in the afternoon.

Report by Tim Harvey on the Marine Wildlife of the North-east Atlantic Ocean Group

24 May 2003
Polurrian Beach, Mullion, Cornwall:  I found hundreds of By-the-Wind Sailors, Velella velella, on the falling tide on Saturday and by the smell/remains they have been coming ashore for several days.

Report by John Hipkiss

21 May 2003
Ray Lawman has reported to Ruth Williams that he there were about half a million Velella velella at "Soapy Cove" on the Lizard, Cornwall.

Report by Stella Turk MBE on the Cornish Mailing List
More Cornish Reports

Thousands of tiny By-the-Wind Sailors, Velella velella, are coming ashore on the Isles of Scilly . Porthlow on St. Mary's (Porthloo on maps) was covered with them, most only about 10 mm in length with only the occasional larger one, and the larger ones were very large at approx. 50 mm, with none in-between. I don't think I have seen them either as big or as small

Report by David Mawer (Isles of Scilly ) via Stella Turk MBE on the Cornish Mailing List

20 May 2003
Hundreds of By-the-Wind Sailors, Velella velella, (a jellyfish-like animal) are washed up on Sennen Cove, Cornwall.
Sennen Cove Wildlife Page

Report by Terry George on the Cornish Mailing List

By-the-Wind Sailors, Velella velella, are being reported again in the sea and washed up on the strandline on the north Cornish shores and Salcombe Harbour, south Devon.

Report from Doug Herdson (National Marine Aquarium, Plymouth)
on the Marine Wildlife of the North-east Atlantic Ocean Group
MARLin Velella Web Page

By 1 February 2003 the westerlies have blown plenty of By-the-Wind Sailor, Velella velella, and the Mauve Stinger, Pelagia noctiluca, on to Sennen Cove, Cornwall, above the high tide mark.

Report by Darren Smith on the Cornish Mailing List

Velella sail (QX3 image by Andy Horton)28 January 2003
Thousands of By-the-Wind Sailor, Velella velella, are discovered washed up, alive or very freshly dead, on Perranporth Beach, Cornwall, together with the Violet Snail, Janthina janthina, (two shells) that preys on Velella. This gastropod is rarely recorded in British seas even when there are large numbers of Velella stranded. It is always worth looking for this attractive and fragile shell.

Rory Goodall has also found large numbers of Velella, on Porthmeor Beach, St Ives, Cornwall.

Report by Paul Gainey from Stella Turk MBE on theCornish Mailing List


15 November 2002
After the recent gales, further large numbers of freshly dead Velella are washed up on the Dorset (Studland) coast with over 50 counted in a stretch of strandline of 100 metres. The dead Velella were still coloured blue which showed that that they have only recently died. They disintegrate and turn white over night. There were live specimens at five miles off the Dorset coast.

Report by Steve Trewhella (Poole, Dorset)
Velella (Photograph by Steve Trewhella)

27 May 2002
"Millions" of Velella velella, the By-the Wind Sailor were discovered by Nick Darke on Porthcothan Beach, Cornwall. They are freshly dead, the float having the animals or at least fragments of the soft tissue, still present. They are probably all along the north coast, especially at Perranporth, so I will be interested to have an idea of the maximum density per sq. metre. The last really big incursion was in June/July 1981 when Rennie Bere counted 150 to 200 per sq. metre, as they came in on the tide (i.e. not heaped up in catchment areas) and he estimated 100,000 for the stretch of shore at Bude.

Report from Stella Turk on the Cornish Mailing List
Many By-the Wind Sailor were also discovered washed up further east on the shore at Kimmeridge Bay, Dorset.
Report by Peter Tinsley (Dorset Wildlife Trust)
On 30 May 2002 thousands of Velella velella were also washed up along the tide line on the beach at Nicholston Burrows on the Gower peninsular, South Wales.
Report by Helen James
> 3 June 2002
Thousands of By-the-Wind Sailors were washed up on the beach adjacent to Rosslare Harbour in County Wexford, Ireland.
Report by Angus Buttanshaw
June 2002
We fished out a specimen of Velella earlier from the middle of Kimmeridge Bay earlier in the week and dropped it in a small pot of seawater.  The pot was quickly filled with lots of small dots which turned out to be medusae, most of which were not fully formed, though a small number were pulsing weakly.
Report by Peter Tinsley (Dorset Wildlife Trust)
via the Marine Wildlife of the North-east Atlantic Ocean Group
Velella (Photograph by Steve Trewhella)On 4 June 2002 many washed up Velella were discovered hidden amongst the pebbles on Aberystwyth south beach, on the west coast of Wales on the shore of Cardigan Bay.
Report by Suzanne Breeze
By 5 June 2002 there were millions of Velella velella washed ashore on Rhosilli beach, a west facing beach at the end of the Gower peninsula in Wales.
Report by John Davies (Swansea University)
Thousands of dead, dried Velella on the beach at Caswell Bay, South Gower, with quite a few live ones bobbing around in the surf too on 10 June 2002.
Report by Adam Cooper
By 8 June 2002 the swathes (thousands) of Velella looked like a 300 metres band of oil washed up on the shore at Freshwater West, Pembrokeshire, SW Wales, from below the car park to Little Furzenip. There was a distinct smell of rotting sea life.
Report by David Saunders via UK Wildlife
By 15 June 2002 millions of Velella had been washed up on the sandy beach of Porth Ty'n Twyn, on the south-west coast of Anglesey (Ynys Môn) between the small towns of Aberffraw and Rhosneigr. The Velella formed five separate strandlines and the stink of the decaying animals was horrendous.
Report by Barry Wright
On 2 June 2002 I have had two reports of hundreds of Velella velella being washed up on the South of the Isle of Man, one report from Scarlett Point and another at Chapel Bay, Port St. Mary.
Report by Mike Bates (Port Erin Marine Lab.)
Also by 10 June 2002, Graham Mercer and the Harbourmaster at Portpatrick, reported thousands of Velella from the inner and harbour at Portpatrick, Dumfries & Galloway, Scotland. This is the most northerly record of the current strandings and they were not known to the local fishermen.
On 15-16 June 2002, smaller numbers of Velella were washed up here on the Isle of Cumbrae. This appears to be the first record in the Firth of Clyde (which has been fairly well studied since the 1880s at least!).
Reports by Dr. Philip Smith (University Marine Biological Station Millport, Isle of Cumbrae)
 13 June 2002 found thousands of Velella were washing in on Kilmory Bay, Sound of Jura, Argyll, Scotland. There was a lot of foam along the tideline at the time and they were quite fresh. This is a south-west facing bay inshore of Islay and Jura in the western islands and the furthest north record for 2002.
Report by Robin Harvey
Scottish Association for Marine Science (SAMS), Dunstaffnage Marine Laboratory
c. 9 June 2002
Thousands of Velella are washed upon the north Devon strandline from Westward Ho!, Croyde and Woolacombe.
Report by Gavin Black (Devon Biodiversity Records Centre)

9 June 2002
Large numbers of dead Velella along strandline of sandy beach at Kilmore Quay (SE Ireland).  Estimated to be in excess of 300 Velella per metre of strandline for about 50 metres (= 15000).  They were a bit dried out so must have been there for a few days.

Report by Jon Moore (Porcupine MNH Society)
23 June 2002
The first dead Velella is washed up on a Sussex beach at Bognor rocks. This is the most easterly record so far up the English Channel.
Report by John Knight (West Sussex Countryside Rangers)
Bionomics of Velella (notes)

15 November 2002
After the recent gales, further large numbers of freshly dead Velella are washed up on the Dorset (Studland) coast with over 50 counted in a stretch of strandline of 100 metres. The dead Velella were still coloured blue which showed that that they only recently dead. They disintegrate and turn white over night. There were live specimens at five miles off the Dorset coast.

Report by Steve Trewhella (Poole, Dorset)

7 December 2001
Hundreds of By-the-wind Sailors Velella velella, are washed up at Prisk Beach (or Prisk Cove) on the rock and shingle shore at the northern mouth of the Helford River, south Cornwall. They were about 5 cm across and despite their large numbers could easily be overlooked. Some sand had also been deposited on the pebbled beach and this is how they were noticed because they stood out from the sand. Some of them had turned white in colour. Is this from decay?
Report by Michael Ennis
In my experience, in south Cornwall, when stranded they tend to do it en masse, with hundreds being normal. Live or recently dead colonies are a striking blue/violet colour. Shortly after death they turn white, and after two to three days all that is normally left are the tough sails, which can remain for some weeks, although often overlooked due to (presumably) being small, transparent, and looking like packaging material. Were any Janthina gastropods noted amongst these strandings?
Reply by Jon Makeham

 6 December 2001
Report from Mr David Leggat.
Cadgwith Cove, the Lizard, Cornwall.  Large (hundreds probably) numbers of the hydrozoans, By-the-wind Sailors Velella velella, between 2 and 7 cm in diameter washed up on this east facing shore.

 Report from Doug Herdson (National Marine Aquarium, Plymouth)
 October 1999
Tens of thousands By-the-Wind Sailor, Velella velella, were discovered by Paul Gainey, washed up on the between Gwithian and Mexico Beach beaches on the north coast of Cornwall. They were also reported at Sennen Cove (near Land's End) by Jayne Herbert. In December 1999, hundreds were reported by Chris Stumbles on a Cornish shore.

     Photograph by Richard Lord

9 October 1999
High up on Saline Beach near the slipway I found a By-the-wind sailor, Velella velella, in good condition.  The pelagic colonial hydroid had most of its tentacles and was a vivid blue colour.          Richard Lord (Guernsey).

Underside of Velella
Photograph by Richard Lord

January 1998
Jon Makeham also discovered about 500 washed up Velella at Looe, southern Cornwall.  This is a lesser number than in previous years.

There are more records of stranded Velella in the BMLSS archives (before 1996 when computer records were collated for the web site entries). Notably, mass strandings in 1992, reported by Amanda Young (Anglesey).


Rhizostoma pulmo    News Report 1999

Norwegian Marine ***
These web pages are recommended for photographs of Jellyfish

  Cnidaria Page

Rhizostoma pulmo

June 2015
Thousands of jellyfish have been reported off the south-western and western coasts off Britain, notable off Dorset and Wales. By far the most noticeable have been the large Barrel Jellyfish, Rhizostoma pulmo but also the huge stinging Lion's Mane Jellyfish, Cyanea capillata.

Barrel Jellyfish washed up at Sandbanks, Dorset
Photographs by Lisa Harris

The diameter of the bell in these jellyfish were up to 75 cm.
BMLSS Jellyfish

22 January 2015

Barrel Jellyfish, Rhizostoma pulmo
Photograph by Margaret Burton

Two large Barrel Jellyfish, Rhizostoma pulmo, were discovered washed up on the shore at Lancing, Sussex.

Report by Margaret Burton

Mystery animal washed up on the Sussex shore
in November 2014
on Beachcombing (British Coastline) facebook

This animal washed up on the Sussex coast proved to be a mystery that was not solved immediately, perhaps due to failure to apply lateral thinking as the creature was washed up in larger than normal numbers around the British coast in 2014. Everybody quickly surmised it was a jellyfish-type animal, but which one? Credit to be first to identify it as part of one of the eight oral arms of the Barrel Jellyfish, Rhizostoma pulmo, came from the Big Jellyfish Hunt.

18 June 2014
One of the more interesting characterisitics of this very wet spring were the numerous reports of very large jellyfish washed up on the southern and western shores of Britain. Almost all of them were the non-venomous Barrel Jellyfish, Rhizostoma pulmo. Reports were recieved from all south-western coasts and many of them were seen in the sea and washed up on the shore of Dorset.

Barrel Jellyfish
Photograph by Andreas Frangou

This blue speciman was a typical sized specimen as others were reported the size of dustbin lids. This was washed up at the Witterings, West Sussex. The most usual colour of this jellyfish is a creamy wide umbrella with trailing tentacles of cream and sometimes brownish-red.

Report by Steve Wallis
21 November 2010
An unprecedented stranding of over a hundred jellyfish Rhizostoma pulmo were discovered on the beach at Formby, Liverpool. "The jellyfish were literally uncountable - we walked about a mile along the beach and they stretched the whole way and out of sight. They were all more than 60 cm in diameter. The previous high tide was accompanied by a moderate wind but nothing exceptional, and was not particularly high."
Two days later, almost all the jellyfish had disappeared with just a few seen stranded on the shore.
Report by Garth Raybould
Marlin Records of Rhizostoma
Formby Times Report
October 2009

I found this jellyfish Rhizostoma pulmo about 200 metres  up from river mouth of River Dysynni, about two miles north of Tywyn on mid Wales coast.
It was about 70-80 cm across, it looked like it was dead and was floating close to the river's edge.

Report by Maria Wagland

8-9 August 2003
Whilst travelling out from Littlehampton marina, West Sussex, on Friday night, we passed four very large Rhizostoma pulmo and counted 21 Compass Jellyfish, Chrysaora hysoscella, over a period of an hour.
On Saturday morning we went armed with cameras. Within 20 minutes we had found three Rhizostomas. The last two were close enough to see the juvenile fish swimming alongside. We dived with the third Rhizostoma for about 30 minutes. It stayed within the top 3 metres of water. We saw a third as we headed back to the marina on a different heading.
Link to the Image by Paul Parsons (Aquapix)
We also spotted eight Compass Jellyfish.

Report by Paul Parsons  on the Marine Wildlife of the North-east Atlantic Ocean Group

Rhizostoma octopus off Chesil Beach (Photograph by Peter Glanvill)

Rhizostoma pulmo off Chesil Beach
Photograph by Peter Glanvill (Dorset)

The sea was exceptionally clear and several large (40 cm + in diameter)  Rhizostoma pulmo were seen off Littlehampton.

Report by Brian Street (Shoreham-by-Sea)

6 August 2003
Doing a few boat transects today we saw absolutely loads of the jellyfish,  Rhizostoma pulmo  off the Rhossilhi/Llangennith beach, Gower, south Wales and further into Carmarthen Bay. I'm not even going to attempt a number, but unless they were all stretched out in lines which corresponded exactly with our transects there must have been tens of thousands.

Report by Adam Cooper
3 August 2003
I saw a huge Barrel Jellyfish swimming in water 100 metres out from Seven Sisters Cliffs (East Sussex). I was fishing for Sea Bass with rod and line on my boat and estimate it to be at least 15 inches in diameter. It was amazing with a purple fringe along the skirt edge. it seemed quite happy bobbing along.
Report by Leigh van den Dolder

14 June 2003
A jellyfish with a bell diameter of 45 cm and one metre long was spotted in calm seas off Shoreham-by-Sea, Sussex, at 7:00 pm. It was creamy white with a pink-blue rim so it was almost certainly the Barrel Jellyfish, Rhizostoma pulmo. These large jellyfish are only occasionally encountered off the Sussex coast.

Report by Tim Worsfield (Shoreham)
10 April 2003
Nick and Jane Darke report a freshly dead Root-mouth Jellyfish on the strandline at Porthcothan, Cornwall.  It has been suggested that large specimens - and this one was two feet in diameter - are ones that have survived our winter. Records will all be entered on the Strandings Database, as they were last year when there were a large number. There have been half a dozen April records over the past 100 years or so.
Report from Stella Turk on the Cornish Mailing List
11 January 2003
Rhizostoma Jellyfish (Photograph by Keith Talbot)A large jellyfish weighing an estimated 15 kg was washed up at Lepe Country Park on the Solent coast in Hampshire (SZ 459 985). The excellent photograph of the underside confirmed this as the first reported specimen of Rhizostoma pulmo for 2003.
Report by Keith Talbot (Lepe Country Park)

28 August 2002
Helen Selvey of Polzeath Voluntary Marine Wildlife Area, has found those small 'green-eyed monsters' for which Paul Gainey has been seeking as he would like to photograph them. When she placed a large freshly-dead Root-mouth Jellyfish, Rhizostoma pulmo in a vessel of seawater, from under it swam a few dozen specimens of a small 12 mm amphipod crustacean called Hyperia galba. They are always associated with one or other of the species of jellyfish, living under the shelter of the umbrella (often within the gonad cavities)  where they are sought by some species of fish. There are only three records on the species database for Cornwall, the latest being 1928 with a 'Plymouth area' record for 1953.  Of course not many people would look for them, but the influx of jellyfish represents a good opportunity - so please 'phone me on 01209 712069 if you find any and can keep them alive in a container in a cool place.

Report from Stella Turk on the Cornish Mailing List
28 August 2002
From the Palace Pier, Brighton, we saw two jellyfish moving very slowly. They were very large we estimated them to be about 130 cm (4-5 feet) in a diameter, a large white dome, medusa with a dark rim, with strange white panel type of things below and then short pale blue tentacles. This is the species Rhizostoma pulmo.
NB. this size may be overestimated.
Report by Kelly Tebb

On 26 August 2002 a species of this jellyfish was seen at a depth of 6 metres over 15 metres of water at the Waldrons, off Littlehampton, Sussex.
BMLSS Jellyfish

Rhizostoma Jellyfish (Photograph by Emma Seaman)August 2002
We found four of these big blue jellyfish, Rhizostoma pulmo, in August washed up on the shoreline of the River Teign between Newton Abbot and Teignmouth in Devon. My husband has size 9 feet, so you can tell they were pretty big!

Report by Emma Seaman.
4 August 2002
We found four large stranded jellyfish on the beach at Marazion, Cornwall. Perhaps this is common, but we were very impressed by their purple colour, size and density; we think they were about 60-80 cm diameter. The photograph showed a white jellyfish which was Rhizostoma pulmo.
Report  by John Stevens
27 July 2002
I saw several (at least 4) 'Root-mouth' Jellyfish, Rhizostoma pulmo, in the vicinity of August Rock buoy near the entrance to the Helford, Cornwall, in the morning. All seemed to be swimming strongly in the direction of Maenporth. Some were on the surface and then sunk as I approached and were swimming some just over 3 metres (10 feet) below the surface.
Report by Nigel Knight on the Cornish Mailing List
Dead Jellyfish at Worm's Head, Gower (Photograph by Roy Dale)

19 July 2002
42 Rhizostoma pulmo, carefully counted, were on the shore at Polkerris near Par, Cornwall, with 50 in the shallows.  About the same time 30 were on Par Beach.
These were the top numbers beached, but elsewhere they were in up to ten on many Cornish shores.  Offshore they were in large shoals  but  of course less easy to count.
But more that one person said they are present this year 'in hundreds if not thousands'.

Report from Stella Turk
17 July 2002
Rhizostoma pulmo jellyfish in Torquay harbour, Devon.
Report by Roy Carter
14 July 2002
50 stranded and very dead Rhizostoma pulmo were by Carnsew Pool in the Hayle Estuary, Cornwall.
Report from Stella Turk

7-9 May 2002
Whilst on Colin Speedie's Basking Shark survey last week we were almost continually among the jellyfish Rhizostoma pulmo (from Lands End to Fowey, Cornwall), some areas had particularly dense aggregations of them.
Report by Gavin Black
Huge numbers of Rhizostoma pulmo were seen between Falmouth and the Lizard, Cornwall.
Report by Peter Tinsley
5-7 May 2002
There have been reports of  jellyfishes from the Cornish and Devon coasts, including Rhizostoma pulmo at 50 cm diameter with a purple rim to the bell stranded near the swimming pool at Devil's Point (Western Kings) on the Plymouth foreshore on 7 May. Richard White (of Devon Wildlife Trust) saw lots of Rhizostoma at Church Cove on the Lizard, Cornwall, on 5 May.
A report arrived via Brixham Coastguard from a member of the public; that a large jellyfish (one metre across) had been found in the Imperial Recreation Ground in Exmouth, Devon, on 6 May 2002.
Report from Doug Herdson (National Marine Aquarium, Plymouth)
via the Marine Wildlife of the North-east Atlantic Ocean Group
Large numbers of jellyfish up to one metre in diameter are also reported from off Chesil beach and around Portland Bill, and also the Erme estuary and Bigbury Bay (south Devon). It seems this is a year of exceptional abundance for Rhizostoma pulmo. (Several reports.) Sea temperature = 12° C.
Aquascope Photographic and Fact File for Rhizostoma pulmo
By 1 June 2002 the Rhizostoma pulmo had reached as far east as Sussex with one specimen of nearly a metre in diameter washed up at Shoreham Beach.
Report by Martin Ward at Adur World Oceans Day
Adur Nature Notes (Spring 2002) for Shoreham Beach Nature Reports

23 June 2002
At least 15  Rhizostoma pulmo  jellyfish, ranging in size between about 10 cm to 60 cm in size were washed up on Studland beach in Dorset.

Report from Doug Herdson (National Marine Aquarium, Plymouth)

26 March 2002
Jean Beason saw a large specimen of the 'Root-mouth' Jellyfish, Rhizostoma pulmo, stranded on the shore at Rock in the Camel Estuary early this morning.
Report from Stella Turk on the Cornish Mailing List

c. 26 December 2001
Isles of Scilly
Ren Hathway  says that Scillonian fisherman, David Thompson, has been trawling up large numbers of the 'Root-mouth' Jellyfish  Rhizostoma pulmo, measuring up to a metre across.

Report from Stella Turk on the Cornish Mailing List
30 May 1999
Isle of Skye
I saw area of approx.' 75 sq. metres (800 sq. ft.) with Moon Jellyfish at approx.' 6 per sq. metre in ever direction, on Sunday 30th. Saw one Moon Jellyfish at least 18" across! never seen one that size before. Today saw two large Rhizostoma's.  Lying stranded on the shore line a 60 cm (24") Lions Mane, all the other Lions Manes we are seeing are no more than 4" to 5" across.
Nigel Smith  (Sea Probe)
Spring 1999
Isle of Man
We had large numbers of Aurelia around during the end of May into June but nothing excessive for the time of year.

There were also large numbers of Rhizostoma about in May.  On the 14 May 1999 I recorded over thirty in the course of a forty minute dive.  Unusually they were distributed throughout the water column; depth of seabed was 26 metres.  Most years at around this time we expect to see half a dozen or so each dive but confined to the top 10 metres.  Now, of course, they are dying off with the remains littering the seabed and forming a food source for a wide variety of species.  We find them with urchins, Echinus esculentus, feeding on them along with the Common Starfish, Asterias rubens, and a variety of gastropods.


Photograph by  Nikki Sheldon (EMail)

News Report

9 June 1999
Six Barrel Jellyfish, Rhizostoma pulmo, were washed up on the sandy beach at Ravenglass, Cumbria, in the north-west of England. The definitive dark blue ring around the base of the bell was present but did not show up on the photograph. This jellyfish does not have stinging tentacles like the similar looking Cyanea species, which are sometimes washed up on the same coast.

October 1995
In 1995 I went fishing in October and remember seeing large numbers of  Rhizostoma pulmo drifting past the boat.

On 6 July 1999, I came across a Marthasterias wrapped around the remains of one (Rhizostoma)  One unusual record was of a group of Metridium on an underwater cliff face that appeared to have captured an Aurelia, possibly a dying one that had drifted onto them.  The grip by the Metridium colony was firm enough to hold it against water being wafted across it by a diver's hand.  Presumably individuals were feeding but I cannot be sure of that.

Report by Michael Bates (Port Erin Marine Laboratory, Isle of Man)
EMail: Michael Bates,
NB:  Records of Plumose Anemones, Metridium senile, feeding on jellyfish on all the venomous species received before on several occasions. AH.

On 27 June 1999, a fisherman reported seeing many of the large jellyfish Rhizostoma pulmo along the South Penwith coast, Cornwall.
Cornish Marine Wildlife Reports 1999 (by Ray Dennis)

News:  Barrel Jellyfish, Rhizostoma pulmo , washed up on the Cumbrian coast. It was discovered stranded on the shore at Ravenglass, which is separated from the Isle of Man by the Irish Sea.

8 July 1999
A swimmer was reported stung by a jellyfish off Ryde on the north-east of the Isle of Wight. The species was not identified. (Colin Pope, IOW Council.)
The only published proven effective first aid treatment for the skin pain of jellyfish wounds is the use of cold packs or ice. Cold is applied to the stung area for 5-15 minutes then re-applied, if necessary. It will stop the skin pain in 98% of cases

Peter Glanvill reports the first specimen of the Compass Jellyfish, Chrysaora hysoscella, (pic) from Seaton, Dorset at the beginning of July 1999. This jellyfish occurs regularly in the English Channel during the summer, but never in the huge numbers of the Moon Jellyfish. The Compass Jellyfish is reputed to have a powerful sting, but I have been unable to verify this with someone who has actually been stung. Sometimes this jellyfish will sting, and sometimes no sting will be felt.

Thousands of Moon Jellyfish reported from the Pembokeshire coast of south Wales by Will Thomas. "Also seen at least 5 jellyfish that are shaped like an oblong bell, about 100 mm (3-4 inches) in length and an electrical green glow passing up and down the centre, I have had no luck in looking up the species so far."
It seems like a comb jelly (Ctenophora). AH.

29 June 2008
We were swimming with many jellyfish at Botany Bay, Thanet, Kent in the evening. In the end we got out of the water as I got stung (didn’t hurt much and left a light rash). We saw about 9 swimming in a very small space but I am sure there were more out there. They were in a range of sizes, the biggest we saw was about 6 – 8 inches across, with very long tendrils and lacy purple markings under the ‘frilly’ bell. It was very beautiful actually, pulsating away through the water. The smaller ones were pinky apricot in colour, with no purple. I have looked them up on the net and think they were Lion's Mane Jellyfish.
They must be flourishing in these Thanet waters because I have found several stranded on the beaches too recently (‘rescued’ one at Westbrook last week).
Report by Sheree Bell
24 June 2007
I have spotted whilst loads of jellyfish, Lion's Mane Jellyfish and Moon Jellyfish whilst I was walking on the beach in Pettycur Bay between Burntisland and Kinghorn in the Firth of Forth Scotland.
Report by David Craig
Photograph by by Linda D'Arcy (October 2001)JonnyChristopherFrancescaLion's Mane JellyfishLulu

Jellyfish discovered inverted on the Newcastle beach (Dundrum Bay), Co. Down, Northern Ireland
by Linda D'Arcy (October 2001)

August 2002
I'm fairly sure I found a Lion's Mane Jellyfish washed up on the beach adjacent to Rosslare Harbour in County Wexford, Ireland in August 2002.  I didn't photograph it but it was similar to the specimen which you display.  It was dark red and seemed to be seeping blood.  In fact, it looked like the internal organ of some creature and it was only when I turned it over that I was convinced it was a jelly fish.

Report by Angus Buttanshaw
25 July 1999
Lion's Mane Jellyfish, Cyanea capillata.
I live in the North East of England and have seen jellyfish of various sizes, between the north and south piers at  Roker, Sunderland, the majority are purple in colour, the one that came across this morning was roughly the size of a dustbin lid. Is this common as I've never seen one this size before?
Thanks Wayne Curtis  EMail:
I think it is probably the venomous species Cyanea lamarckii. However, it is just possible that it is the species the Lion's Mane Jellyfish, Cyanea capillata. AH.
 The sting is reckoned to be less painful than a wasp sting. The wound is best washed in fresh water. Some people are allergic to the stings. AH (from Emails from Tyneside and Norway)
"The purple jellyfish are mainly between the north and south piers at Roker Sunderland, in the wash quite close to shore. We have a lot of the white ones but they all seem to be along the pier wall for some reason. The dustbin lid size jellyfish at Roker was in the same place very early morning it was washed up on the sand it looks like the one in the pic Velella. There have been no warnings of stinging jellyfish but my wife has informed me that we did have a warning last summer about the Lion's Tail variety. The colour in a way I can describe the bigger the are the stronger the colour, the dustbin lid size was a really
dark colour and about 12 - 15 cm (5-6 inches) thick. Nobody was on the beach at the time. We've also get a few large dark red one. Are these related? These are normally further out in the bay and not as many. The small white and small purple ones are quite common but it was just the pure size of the large purple one which had me interested."
   Lion's Mane Jellyfish
"The winds have been north-westerly and then north-easterly preceding the jellyfish strandings."
 Photographs & Report by Wayne Curtis (Sunderland)
News Report of Lion's Mane Jellyfish
  In early July 1995 a giant jellyfish was found washed up on the shore outside the Museum of Galloway Life in Gatehouse of Fleet (SW Scotland). It was discovered by Neil Barclay and weighed 9 kg (20 lb). It measured 61 cm (24 in) in diameter. The species was not identified in the report, but it was probably the Lion's Mane Jellyfish, Cyanea capillata. This species is dangerous with numerous stinging cells that can be painful to humans.
Moon Jellyfish, Aurelia aurita, recorded in Shoreham Harbour, Sussex  (1995) and every subsequent year.

It is possible that the Lion's Mane Jellyfish, Cyanea capillata, have been recorded in large swarms of the Sussex coast in the past. The jellyfish were described as purple with long stinging tentacles, so they could have been the Portuguese Man-o-War, Physalia physalis. Lion's Mane are frequently described as purple in colour. (Brian)


I was stung by a Lions Mane jellyfish today while diving in Babbacombe, Devon in the summer of 2001.   I was about 150 metres from shore at about 11:00 am.  Depth, around 7 metres.

I looked up, saw tentacles in front of my face. Momentum carried me right into them.  Hurt like nettles or a wasp sting.  We treated it with malt vinegar (not recommended) and antihistamine cream.  Pain subsided about 1 hour later.  No marks remaining (12 hours later).

I hope this information is useful to you.

Richard Williams
Taunton, Somerset
07754 398 512


Jellyfish Report from the Isle of Lewis, Outer Hebrides.

4 August 2002
Quite a few largish Compass Jellyfish, Chrysaora hysoscella, around just now (15 cm diameter) seen close to my local pier (West Loch Roag) - I saw six actively swimming ones in an area about 100 metres square.

More interesting is the reported death and destruction wrought on Salmon farms on the east coast of Lewis by small jellyfish clogging the salmon gills. A fish farmer claims its a foreign species introduced by ballast water, but I need to try and confirm this. Apparently they are 'solid down to 15 metres' so there must be a lot of them; allegedly the mortality is so great that local facilities for disposal are overwhelmed and they have to take them to Shetland for disposal!

Report by Paul Tyler



Sting Reports

Jellyfish Guide
by Matt Fletcher

7 September 2012
Portuguese Man o'War washed up on Cornish shores and it stung a young lad. BBC Video Interview.

BBC News Report & Video
Latest (2010) discussion on the Cnidaria News Group (Link)

Diver's are rarely stung by jellyfish in British seas because there is hardly any skin exposed: the water is too cold.

Portuguese Man o'War (Photograph by Dr Gerald Legg)I've been stung a couple of times by  Physalia (Portuguese Man o'War) in the Azores. On one occasion I was swimming round a fishing buoy where a detached tentacle was stuck, so the jellyfish itself was not to be seen. It felt like a wasp sting but had no lasting effects. A small rash appeared on my arm which lasted for a fortnight.
I was stung whilst diving off the Summer Isles (W Scotland) across the upper lip by a tentacle several feet in length belonging to
Lion's Mane Jellyfish well above me in the water, or so I thought! That too felt like a wasp sting or being thrown into a bed of nettles. Alarming at the time (40 ft deep) but no lasting effects.
Bill Farnham (Univ. of Portsmouth) (received September 1999)

4 August 2008
I discovered a Portuguese Man-o'-War, Physalia physalis, on Southsea seafront, Portsmouth, to the east of the pier. The sting on the palm of my hand was mild but persistent and still felt ten days afterwards.

Report by Adam McGonigle
Dear Andy,
I got a dollop of Lion's Mane in my eye once, pulling a fishing net over the side of a boat. Within about 12 hours I had an abscess that required antibiotics to clear. In general the stings I have received on hands arms and face feel more like an acid burn and don't leave a wound.
Regards from Nigel Smith (Sea Probe) September 1999

A swimmer was reported stung by a jellyfish off Ryde on the north-east of the Isle of Wight. The species was not identified. (Colin Pope, IOW Council 1999)
PS:  I have received one report from Wales of a child developing a rash after being stung by a small transparent jellyfish. AH.
(see the note below, click on this text).

A swimmer was stung whilst swimming off Norfolk, (North Sea) and received medical treatment. The arm swelled up and felt stiff.
Report by Jane Fowler-Tutt.

A bright red weal depending on the length of the tentacle or fragment. I've been stung by strands from a Portuguese Man o'War, Physalia. All the marks were vivid & bright red, but not necessarily raised. But all very sore.
Philip Vas

A detached tentacle of Cyanea sp. (both C. capillata & C. lamarckii were present) caught me across the cheek and upper lip when I was diving in NW Scotland. It prickled like a really bad nettle sting, painfully for about 24 hours.
Jane Lilley (Newdigate) (received September 1999)

Although the Canaries are not NE Atlantic we do have a lot of cases of Jellyfish and Anemone stings. The wound of a jellyfish tends to be very similar to the wound of stinging nettles. However the Jellyfish sting tends to be more linear as opposed to the small white dotted sting of the nettles.
The immediate surrounding skin surface also tends to swell gently and is slightly enflamed. The treatment is relatively simple as it involves rinsing the sting in fresh water and then gently but liberally dousing the sting with an anti inflammatory product which can generally be found in most supermarkets or chemists.
Mark Thorpe.

I have just returned from Brittany and found your  request which had been passed on via NERC.  There is some information on Jellyfish stings in: The Medusae of the British Isles , by F.S. Russell.  Published in two volumes by CUP in 1953 and 1970.  Some details are given under each species which is known to sting and there are quite a lot of references to stings and their effects -  F.S. Russell was actually stung by a Lion's Mane on the Great Barrier Reef.  The people that I have seen stung in British waters have a long trail of what looks like a very severe nettle rash.
                         I hope this is of some help.
                                     Yours sincerely,
                                                      Gerald T. Boalch

Although it is more an anecdotal story, I recently made an interesting experience in the variability of the individual response to jellyfish stings.
While swimming in the Mediterranean, my daughter (7) and I (41) were simultaneously stung by the same individual of Pelagia noctiluca. The surface of the burns was comparable (legs and arms) and the initial reaction was identical: pain, blistering (urticae), swellings etc. We treated the sting with an antihistaminic (Fenistil jelly). My daughter's burns were completely gone after 2 hours and did not re-appear. However, my stings persisted for nearly 10 days, itched incredibly, and the tissue
became necrotic in the end (lost skin). The surrounding tissue was swollen and hot for several days.
It was the first sting my daughter experienced, while I have been stung quite often by Cnidarians (Pelagia, Millepora, Aglaophenia, Physalia, Pennaria (it stings!), partly accidentally, partly experimental). So I concluded that most likely also previous exposure can determine the reaction to cnidarian stings.

kind regards,
Dr Peter Schuchert                                   Hydrozoa worldwide

Museum of Natural History
Dept. of Invertebrates
1, route de Malagnou
CH-1208 Geneva

I've been stung by a Physalia (Portuguese Man o'War) in the Mediterranean, one tentacle hit across the back, and the wound looked and felt much like I guess a whiplash must, a neat line, perhaps 3 mm wide, extending from my neck to the hem of my swimming trunks.

From: Mike Noren (Swedish Museum of Natural History & Stockholm University)

Unidentified sting from a jellyfish (or sea anemone)?

Last week (June 2002) my daughter was in the sea off the coast of Northern France at Berck-sur-mer, we think that she was stung by a jelly-fish. There were 100's of 50 pence piece size clear 'jelly-fish' left on the beach as the tide went out as well as in the shallow water.
Having been in the sea she appeared with two weals across her shoulder and back around these the skin was very red and angry looking, it was hot and sore to touch. She also had slight blistering spotting across her back around the mark. After about a week the patch of skin eventually blistered up and then peeled, the two weals being the last to heal as the wound seemed to have gone deeper here. Ten days later her skin still looks very raw and has darker patches across the wound.
My daughter is 9, she was playing in water that was at the maximum about 2 feet deep, it was a sandy beach with no rockpools etc., we didn't see any other sea creatures such as anemones. The beach is in a fairly big tourist resort and was full of people however very few were in the sea  - it was early evening when we were there.
We didn't realise Molly had been stung - it didn't hurt at the time but was only sore afterwards.
The jelly-fish were translucent whitish with slightly dark segment marks.

Carrie Hardwick

This injury could have been caused by the Snakelocks Anemone (from rocky shores and shallow seas).

9 November 2003
Recently spotted a Lion's mane in Key Largo Florida.  Bell was approx 2 ft in diameter and tentacles were at least 25 - 30 ft long..  It stung a number of divers.  don't know if you're collecting this info or if its helpful, just found your email on a link while researching what we had found.  don't hesitate to contact me if you have a need for more questions.

On the Cnidaria Discussion Group


  Thanks for the reply. We holidayed in Greece last June (2005) and my youngest daughter (6) had a bad sting. She had a very mild one with tentacle lines that faded in a day the first week of our holiday. However int he second week she was playing in the shallows - the first part of which is all rocky. She was pulling herself along through the rocks on all fours. She came running up the beach screaming and the 'tentacle' lines where immediatly visible on her leg. I had antihistamine tablets on me and immediatly gave her one and we took her to first aid where they applied a general sting lotion/jelly. The lines had immediatly turned a dark purple on her leg. Over the next few days they became raised very sore and split open. We had to see a doctor as the area became red/hot and inflamed and was obviously infected. She was given antibiotic cream which didn't have much effect. On our return  to Engaland we took her to the doctor who gave her oral antibiotics. By the time the main wound was raw, open and all the wounds looked like she'd been slashed with a knife. The main wound was about 4-5mm deep open flesh. The doctor described it as looking like a chemical burn.

  It still didn't heal that well and she had to go on a second course of stronger antibiotics and eventually it healed - over the next couple of months.

  Shes been left with a largish purplish scar where the deepest wound was - about 2 cm in length - and faint white scars where the other lines/tentacles were.

  The odd thing was that we never saw any jellyfish at all - and neither did anyone else there - including staff. The rocky area is under water, about 2ft wide and you walk over it as you walk out to sea - its then all sand - this is covered in lots of coral looking 'stuff'!

  We're returing to the same place this year - at the same time!! - and I'm just curious as to what it was. Could it have been anything other than a jellyfish (urchin perhaps) - we didn't see any of these either but it was the wavy tentacle lines on her that made us think it was a jellyfish. There was nothing in the wound when she came out of the sea.

  I'd be really interested to know what you think.
  Thanks for your help

  Jenny Neale

I think this is probably the jellyfish immediately below:


25 November 2015

Mauve Stingers at Perranporth
Photographs by David Fenwick Snr

Ten thousands of small (about 20 mm diameter) Mauve Stingers, Pelagia noctiluca were washed ashore on Cornish beaches, notably at Perranporth and Porthtowan and other locations on the exposed north coast. This small jellyfish has a reputation a a stinger.

Report by David Fenwick Snr & others on NE Atlantic Cnidaria  facebook
Pelagia noctiluca, Connemara, W. Ireland. Sept 1999 Jim GreenfieldI had an unfortunate encounter with Pelagia at the Azores a couple of years ago, while swimming.  Although I only slightly came in contact with the tentacles of the jellyfish (on my chest), the sting was VERY painful.  It could be described as a whiplash (although I cannot say that I have been whiplashed before...). At the beginning of May, some beaches in the south of France had been closed for swimming for a short while, because of the
presence of this jellyfish (probably often the case in the Mediterranean).
Jan Haelters

23 June 2003
I plucked one straight from the sea and held it in my hand for ten minutes and it had no effect whatsoever. Mass stranding on the N.Cornish coast
Nick Darke

Pelagia noctiluca, Connemara, W. Ireland
 September 1999, Photograph by Jim Greenfield
June 2003
I only experienced a very mild irritation from the Pelagia when hauling in the umbilical on the drop-down vid.  But nothing really painful. (Lundy)
Ian Reach (Maritime Protected Areas Officer, English Nature)

The sting from Pelagia can be terrible. My daughter (aged 6 at the time) was stung on her thigh in Yugoslavia. She was in agony for a couple of hours and had a scar on her leg which you could still see after 10 years. I know of a similar case with a young child which resulted in lasting scars.
I have seen Pelagia many times in the Med. where it is not uncommon to close beaches because of their presence. Also have seen them in good numbers off W. Ireland. I have put a picture in the (appropriate?) album.
Jim Greenfield

Click on thsi image to link to the latest information fileTreatment of Stings  (Warning there is no consensus on the best treament)

First Aid For The Treatment Of
Jellyfish Stings

The only published proven effective first aid treatment for the skin pain of jellyfish wounds is the use of cold packs or ice. Cold is applied to the stung area for 5-15 minutes then re-applied, if necessary. It will stop the skin pain in 98% of cases.

        Dr Peter Fenner
I was interested in Andy Horton's reports on the incidence of jellyfish in the UK. I would like to see more such reports from worldwide. However, I would like to add additional comments on Andy's suggested treatment of jellyfish stings.

"The most useful preparation for a jellyfish sting is hydrocortisone cream"

Although this may be of benefit in a delayed allergy to jellyfish venom, which occasionally occurs with cubozoans and very rarely in other species, it has not yet been statistically proven to help the toxic venom effect of a cnidarian sting. Delayed allergy to a jellyfish stings usually occurs some 10-16 days after the initial sting and is usually heralded by the re-appearance of the jellyfish tentacle marks which are intensely itchy.
However, cortisone based creams are weak and often ineffective and ultra-potent steroid creams, or preferably oral prednisone is much more effective (Williamson et al 1996). Hydrocortisone cream in the early sting may also suppress the inflammatory response and allow infection, which does not respond to "usual" antibiotics used for skin infections (Williamson et al 1996), it has never been proven to give any benefit in published journals on randomised or double blind treatment trials.

The only published proven effective first aid treatment for the skin pain of jellyfish wounds is the use of cold packs or ice. Cold is applied to the stung area for 5-15 minutes then re-applied, if necessary. It will stop the skin pain in 98% of cases (Exton et al 198 ). Heat makes the envneomation worse (Williamson et al 1996). Other plant extracts and many other chemical
reagents have been suggested to stop the skin pain but there are no double blinded or randomised trials to prove their claims. Vinegar is only useful, but very effective, for preventing further discharge and removing adherent tentacles after cubozoan stings (Williamson et al 1996). It may make other stings worse (Fenner and Fitzpatrick 1986, Fenner et al 1993) and should
not be used.

Other symptoms, including systemic symptoms are dealt with in the usual manner by qualified medical practitioners.

I would be happy to answer other questions on the treatment of jellyfish


Peter Fenner

Exton DR, Fenner PJ, Williamson JAH. 1989. Ice packs: an effective first aid treatment for Physalia and other painful jellyfish stings. Med J Aust 151: 625-626.

Fenner PJ, Fitzpatrick PF. 1986. Experiments with the nematocysts of Cyanea capillata Med J Aust 145: 174.

Fenner PJ, Williamson JA, Burnett JW, Rifkin J. 1993. First aid treatment of jellyfish stings in Australia: response to a newly differentiated species. Med J Aust 158: 498-501.

Williamson JA, Fenner PJ, Burnett JW, Rifkin J, editors. Venomous and poisonous marine animals: a medical and biological handbook. Surf Life Saving Australia and University of New South Wales Press Ltd, Sydney, 1996.

Dr Peter Fenner
National Medical Officer
Surf Life Saving Australia

 Williamson JA, Fenner PJ, Burnett JW, Rifkin J, editors. Venomous and poisonous marine animals: a medical and biological handbook.
Surf Life Saving Australia and University of New South Wales Press Ltd, Sydney, 1996.

Dr Peter Fenner
National Medical Officer
Surf Life Saving Australia

 Vinegar totally inhibits the firing mechanism for the nematocysts of every  cubozoan tested to date. Chirodropids usually have adherent tentacles that are torn off and remain on the skin. The longer they remain on the skin, the greater the envneomation as more nematocysts fire. Vinegar prevents this. However, vinegar causes all (most?) of the nematocysts of Cyanea to discharge and in some Physalia species (approx. 30% of the Pacific P. physalis) - I subscribe to two species, P. utriculus, single tentacle and common in Australia, and P. physalis, multi-tentacled, (medium size in the Pacific, smaller than the Atlantic species that has caused 2 deaths). I haven't tested other species but would be interested in the input of others.
> Peter Fenner

All of the nematocyst venoms studied thus far are mixtures of proteins.
Hence, the superficial rationale for papain. On the other hand, it is not apparent why papain should be efficacious, since papain can neither penetrate the undischarged nematocyst capsule to hydrolyse the venom contained within, nor can it get into the skin to reach the venom injected from the discharged nematocysts.  The best that I can figure is that papain may (?) help to inactivate undischarged nematocysts and cnidocytes still adhering to the skin, thereby helping to prevent any sustained stinging subsequent the initial contact between the skin and the tentacles.
    Anyone else have any ideas? How about Joe Burnett?

Dave Hessinger
Dept. of Physiology and Pharmacology
School of Medicine
Loma Linda University
Loma Linda, CA 92350
(909) 824-4564


Hot water is reported in a single test showed hot water to increase the sting pain at first but afford permanaent relief after 20 minutes.

Press Report (click on this text)


Other stings and irritants (British seas only):

Lamprey Attack
Stings from Sea Anemones (SW Britain)
Sting Pain Index
Beware of the Weever
Dogger Batch Itch file
Zoonosis Notes

Electric Ray, Sting Ray, Whiteweed and other hydroids, Alcyonidium (a bryozoan) = "Dogger Bank Itch", King Ragworm, fine needle diatoms of the Nitzschia type, + others.

Even the Blenny can draw blood and the Velvet Swimming Crab can surprise the rockpooler with the suddenness of the nip which does not prove to be dangerous. Any fish with sharp teeth can cause an injury.

Jellyfish Sting Newsletter

Selected extracts of the pages:

Number 7 July, 1992

Kokelj F, Stinco G, Del Negro P. Dermatotoxicity of the Adriatic jellyfish. G Ital Dermatol Venereol 1990; 125:575-577. Published in Italian. Unique identifier: 91224687

The toxicity of purified nematocysts preparations from Aurelia aurita, Chrysaora hysoscella and Rhizostoma pulmo was studied in 25 volunteers by a scratch-patch test. Low amounts of dermatotoxicity was demonstrated and this testing could be used as a measure to purify active preparations from the venom.

Kokelj F. Contact dermatitis due to the Adriatic Sea jellyfish. Presented to the 2nd Congress of the European Academy of Dermatology and Venerology, Athens, October, 1991.

Ten different species of Sciphomedusae are present in the Adriatic but only four were found to be dermotoxic: Pelagia noctiluca, Aurelia aurita, Rhizostoma pulmo and Chrysaora hysoscella

No. 19

Queruel P., Bernard P., and Dantzer E. Severe cutaneous envenomation by the Mediterranean jellyfish Pelagia noctiluca. Vet. Human Toxicol. 1996;38:460.

Pelagia noctiluca is an endemic Mediterranean jellyfish appearing in abundance every 10 or 12 years. During these proliferations, when the swarms of medusae come to the beach, envenomations increase significantly. Generally, the stings produced minor cutaneous reactions such as erythematous and pruriginous eruptions, but some lesions were more dramatic or envenomations in the form of "burns." All these patients had a history of previous minor stings by Pelagia. None of the patients had general symptoms when stung. Post inflammatory pigmentation lasted several months but resolved spontaneously.

Paul Cornelius of London has relayed to my Australian friends that Aurelia around the UK is capable of inducing human skin pain.

Faisal Radwan of Egypt, wrote that Aurelia aurita from the Red Sea can sting human skin.

Number 3
July, 1990

Exton, DR, Fenner, PJ and Williamson, JA. Cold packs: effective topical analgesia in the treatment of painful stings by Physalia and other jellyfish. Med J Aust 151:625-626, 1989.
In this study cold packs taken from household freezers were applied to the envenomated area for 5 to 10 minutes then reapplied for additional similar periods if the pain had not subsided. One hundred and forty-three patients were studied, 16 of whom had severe, 45 moderate and 82 mild pain. Good results were achieved and the only significant failures were in the severe pain group (25%). However, the severe pain from Chironex envenomations were not effectively treated by this maneuver in two instances

We have reviewed the known lethalities from Physalia physalis and have uncovered in newspaper clippings two more teenagers who died in the 1970's. These, added to the three already described in medical journals, brings the total to five.

Sting Pain Index

Introduction to Dive Medicine

Handbook of Clinical Toxicology of Animal Venoms and Poisons

Editors - Jürg Meier, University of Basel, Switzerland and Julian White, State Toxicology Services, South Australia , University of Adelaide Medical School, State Poisons Information Center, South Australia, Australia

International Conference on Jellyfish Blooms

'A Scientific and Societal Agenda'
12-14 January, 2000
Gulf Shores, Alabama

Plankton Blooms (includes Jellyfish) in the Times 30/7/99

Eumatzoan Zooplankton

Understanding Jellyfish in the Irish Sea

Norwegian Marine ***
These web pages are recommended for photographs of Jellyfish

Cnidarian Page (with jellyfish-like animals)

A few Extra Notes

IMAGES  on flickr

Images of British Cnidarians
Cnidarians of the World
Sea Anemones

Jellies Zone

Synopsis of the Medusae of the World

Cornish Marine Wildlife Reports 1999 (by Ray Dennis)
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