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Actinia equina

(Linnaeus, 1758)


Andy Horton Actinia equina

Message posted on NE Atlantic Cnidaria on 15 Feb 2013
Andy Horton Double-headed Actinia equina

Andy Horton Who does the Beadlet Anemone, Actinia equina, reproduce?

Andy Horton Should read: How does?

Shôn Roberts Can anyone tell me what this is. I think its a Beadlet Anemone. But not sure.

Paul Turkentine Looks like a closed beadlet anemone, Actinia equina....

Rohan Holt Yup. Looks right.

Message posted on Seasearch North Wales on 22 Apr 2012
Nicolas Jouault What are these anemones?

Chris Barrett Actinia equina, just in white I believe

Andy Horton Probably Actiinothoe

Nicolas Jouault It appeared alive, the tide was coming in so I just took a hurried picture. Thanks for all the suggestions.

Andy Horton Actinothoe are often (usually?) lightly adherent. This is a highly probable ID.

Bernard Picton I was just looking at NBN mapping and found that people have been recording Actinia fragacea all round the UK. I think these are just the spotty version of Actinia equina. I don't have good photographs of A. fragacea, but would be interested to hear your opinions and see some photographs. A. fragacea is supposed to be confined to the south coast of England.

Bernard Picton This one is from southern Portugal.

Andy Horton Actinia equina can change into a full blown Actinia fragacea if you judge by appearances. Sussex coast specimens. I have kept them in captivity for over 10 years, possibly 15 years. This century I have not found so many Actinia fragacea as I have not been to the best locations. http://www.glaucus.org.uk/fragacea.htm

Andy Horton A typical Sussex specimen is likely to have pale tentacles: http://www.glaucus.org.uk/fragacea.jpg

Andy Horton This one was put down to Actinia equina: http://www.facebook.com/photo.php?fbid=10150902996844065&set=oa.387114391301613&type=1&theater Not really enough spots for A. fragacea ???

Andy Horton This particular anemone got be hooked on needing to takes its portrait: http://www.glaucus.org.uk/Fragacea-2.jpg It was kept in captivity for over 12 years. Despite its pale tentacles it it its full complement of spots typical of Actinia fragacea. Unlike the normal Beadlets, it showed no sign of reproducing over all those years. I lost it to a Tompot Blenny which I did not know ate sea anemones at the time.

Becky Hitchin Simply from field observations, I'd say that fragacea are generally larger than equina, lower on the shore and more often in damp / wet places. But that's just ecological preferences.

Andy Horton I find that my field observations from Sussex that red, green or brown specimens are often found together. In captivity they can change colour over a period of weeks or months. Only brown or red specimens get green spots. The largest specimens are found on lower shore mussel beds, but not on all of them.

Jon Chamberlain I was very excited to "discover" Actinia fragacea in Eyemouth, only for Dawn to correct me that it was just Sagartia elegans (which is red and spotted when closed up). It just shows how important a good IDing network is to double check sightings. http://www.flickr.com/photos/underwaterinferno/8088015887/in/set-72157631770525541

Becky Hitchin Jon Chamberlain, I just did the same with a "strawberry" in Cove Bay ...

Message posted on NE Atlantic Cnidaria on 16 Oct 2012
Andy Horton This is for the colour (not edited) and the few green spots. I think that Actinia equina and Actinia fragacea are the same species (depending on the the definition of species).

Message posted on NE Atlantic Cnidaria on 11 Jun 2012
Andy Horton These two sea anemones are having a fight. Anemonia viridis and Actinia equina.

Andy Horton Actinia equina displays aggressive behaviour towards neighbouring individuals. This aggressive behaviour is stimulated when the tentacles of adjacent anemones come into contact. The aggressor stings the victim with nematocysts, in the acrorhagi, which leads to the victim either crawling away or dropping off the substratum. The strawberry anemone, Actinia fragacea, is more plump than Actinia equina and is red to reddish brown in colour with greenish spots (Manuel, 1988). http://www.marlin.ac.uk/speciesinformation.php?speciesID=2359

Andy Horton Note the first use of scientific names in this case. However, in these two species the name Snakelocks and Beadlet are commonly used (English language). The pronunciation of the species name for Actinia varies.

Bernard Picton Gosse's names are OK, but inventing new ones isn't a good idea in my opinion. Ask any European if they've seen any glaucous pimplets recently and you'll get a blank look. QED.

Andy Horton The trend would seem more likely the removal of unsuitable common names. They cause more problems than scientific names.

Message posted on NE Atlantic Cnidaria on 06 Feb 2012
Andy Horton 19 May 2011 A large plain green specimen of the Beadlet Anemone, Actinia equina, collected on Worthing Beach on 18 April 2011 suddenly diminished in a manner seen before in the Actinia sea anemones. The green specimen with a basal diameter of approximately 60 mm and a larger tentacle span shrivelled up into a smaller version that looked as though it might be dying, and the tentacles became thinner than those of the Snakelocks Anemones, Anemonia viridis, and the oral disc disappeared from view covered by the partially retracted tentacles. On 20 May 2011, I noted that sea anemone had returned to its normal appearance. On 21 May 2011 I noticed that its column was covered in spots which were pronounced enough to be nearer in appearance to the designated species Actinia fragacea. Its spots were distinct light green but the background colour of the column became brown rather than red. It was slightly smaller with a basal diameter of about 50 mm. Intermediate forms or Actinia equina with green lines and spots are known to occur occasionally. This anemone has green tentacles whereas the usual "strawberry type" has crimson or red tentacles. http://www.glaucus.org.uk/Beadlet.htm

Andy Horton http://www.habitas.org.uk/marinelife/species.asp?item=d11510 http://en.wikipedia.org/wiki/Beadlet_anemone

Bernard Picton Thanks Andy, but I wasn't wanting reposting except in response to someone else's query. We've got this one secret so far so we'll need to set a good example.

Bernard Picton cross-posting I mean I suppose.

Bernard Picton Good start though, think of other people who are quite knowledgeable on Cnidaria and add them.

Andy Horton I have not posted this anywhere else and there is no link to this group from anywhere else. I will leave it up to you to advertise the group. But if you do not advertise it, somebody else will set up a group sooner or later. Facebook isn't very precious. I am not sure facebook is best for serious specialist groups. Yahoo Groups might be better? Spam can be an occasional nuisance for administrators. I have not found it to be the case.

Bernard Picton I don't want to generate work, just provide a resource. I'll make the group into closed status as soon as there is something to look at. I made the mistake of starting Seasearch Tunicates as a closed group and had people clamouring to get on while there was nothing yet there.

Message posted on NE Atlantic Cnidaria on 06 Feb 2012
Andy Horton 4 June 2012 A rockpooling visit to Worthing Pier on a low (0.4 metres) spring tide produced a surprise Brittlestar as well as some infrequent summer occurences like two large Velvet Swimming Crabs, Necora puber, a handful of small Common Hermit Crabs, Pagurus bernhardus, in winkle shells, a single Common Starfish Asterias rubens, one Dahlia Anemone, Urticina felina, one small Long-legged Spider Crab Macropodia rostrata, and one sub-adult 5-Bearded Rockling, Ciliata mustela. A Greater Pipefish, Syngnathus acus, was rescued from the beak of a Herring Gull. Daisy Anemones, Cereus pedunculatus, were frequently found in chocolate brown hues. Snakelocks Anemones, Anemonia viridis, were common as usual with frequent Beadlet Anemones Actinia equina. Full Rockpooling Report http://www.glaucus.org.uk/LancingBeach2008.htm#4June (This came out like a list: I must be a bit tired.)

David Hill David Hill Andy - went on a Bioblitz on Saturday at Cemlyn Bay (north coast of Anglesey) and today rockpooling at Llanddulas (north Wales coast) - lots of interesting new finds (for me anyway, fairly new to marine life). Cemlyn included Eel, 5-Bearded Rockling, Butterfish, Lobster and Great Scallop - a few pics here www.flickr.com/photos/natureseye/sets/72157630042354134/ and list of species here http://www.cofnod.org.uk/BioBlitz?ID=6 At Llanddullas this afternoon lots of Sea Gooseberries and a few Pipefish, pics to follow.

Andy Horton The Greater Pipefish did not look injured when collected, but I do not think it will survive. The gulls catch these pipefish occasionally and drop them in gardens.

Joe Bater that would have been a great UW macro photography day!

Andy Horton Not so good on the photography front. Pier causes shadows and low light. Capture and return. I hope to get a few shots later. I was terrestrial and the critters were under rocks. More though. The young rockpoolers (8 yo) are well informed now.

David Hill http://www.flickr.com/photos/natureseye/7340913120/

Erling Svensen Do anybody know why this Sagarthia elegans anemone have a couple of very long arms? The anemone is only 1,5 cm across the disk.

Andy Horton The tentacles enlarge and subject of my talks at the Coelenterate Society and probably Porcupine Society talk way back in the past (20th century). It was on Sagartia troglodytes.

Andy Horton Feeding As many as five large 'catch tentacles' seem to be enlarged versions of existing tentacles, and these can be best observed in aquaria. They are usually translucent. In the wild, this anemone is known to eat shrimps and small crabs that are 75% of the bulk of the anemone, and these tentacles would be necessary to manoeuvre the prey to the mouth. They will actively search the surrounding water for prey of mostly small crustaceans. Catch tentacles are controversial in a number of ways: 1) They are recorded as not existing in preserved specimens in species like the Plumose, Metridium senile, in which they are actually quite common. This is because they are not separate tentacles. http://www.glaucus.org.uk/S-troglo2.htm Pictures are still on the old slides and have not been copied.

Erling Svensen Thanks Andy. Very informable and I did not know. Very nice to observe and learn new things.

Andy Horton These are my anecdotal observations and conclusions from the evidence. In 1993 it was new.

Ron Ates Nice picture. These elongated tentacles have been seen on several more species of acontiarian sea anemones. In S. elegans since at least 1860 or so. They are called fighting tentacles (previously catch tentacles) for their ability to damage neighbouring sea anemones and other animals.

Andy Horton I tested the this "fighting bit" in both Sagartia troglodytes and M. senile by putting the sea anemones next to each other. The tentacles did not enlarge. I put live food in the water and tentacles cames out to try and catch the food. In Actinia equina the acrorhagi seem to be used for fighting, or possible the tentacles do the opposite and retract when they bump into each other. Best results occur when Actinia is matched up against an Anemonia Snakelocks. I repeated the feeding experiment about a hundred times. The catch tentacles did not always appear but they did at least a dozen times out of a hundred, possible more. In eh Beadlet, Actinia the tentacles retract most readily but also in M. senile and the A viridis as well.

Ron Ates Hi Andy,

Ron Ates Hi Andy,

Ron Ates Hi Andy, you raise interesting points, let's compare notes. I am new to this facebookstuff, sorry for that. Things may go wrong as I must learn. I agree that the evidence can be tricky. For instance Diadumene cincta, which is very common in the Netherlands shows fighting tentacles all the time. Yet I have never seen aggressive interactions with other anemones. However, Manuel (1981:122) witnessed it in a fight with Anemonia viridis (your snakelocks) and the latter was killed. So I conclude that elongated tentacles may kill competitors. Another thing that seems to be clear from the literature is that food never adheres to these elongated tentacles. Would you like me to send you pdf's of what I have on this subject?

George Brown Welcome to facebook Ron. Your pdf's sound interesting.

Andy Horton Yes please. There is a files section that *.pdf files can be uploaded to. I don't think I have seen Sagartia actually eat at all. I have seen them spit out tiny Shore Crabs. More later.

Ron Ates Please see Purcell (1977) for an account of fighting tentacle behaviour in the plumose anemone Metridium senile. Food does not adhere to them. They are used in aggression. As far as Sagartia elegans is concerned I have seen it damage and chase away snakelock anemones in my aquarium. Admittedly, in other species the function of elongated tentacles is not always as clear. I will now try to upload part of Purcell (1977), keep your fingers crossed.

Andy Horton The main function of my observations was that they were elongated tentacles rather than separate tentacles.Then there was how to induce the sea anemones to eat which was achieved by introducing food to the water &/or fresh sea water and it was then that the tentacles were observed. When tentacles of other sea anemones meet each other I observed retraction more often than not.

Message posted on NE Atlantic Cnidaria on 24 Sep 2013
Bernard Picton I was just looking at NBN mapping and found that people have been recording Actinia fragacea all round the UK. I think these are just the spotty version of Actinia equina. I don't have good photographs of A. fragacea, but would be interested to hear your opinions and see some photographs. A. fragacea is supposed to be confined to the south coast of England.

Bernard Picton This one is from southern Portugal.

Andy Horton Actinia equina can change into a full blown Actinia fragacea if you judge by appearances. Sussex coast specimens. I have kept them in captivity for over 10 years, possibly 15 years. This century I have not found so many Actinia fragacea as I have not been to the best locations. http://www.glaucus.org.uk/fragacea.htm

Andy Horton A typical Sussex specimen is likely to have pale tentacles: http://www.glaucus.org.uk/fragacea.jpg

Andy Horton This one was put down to Actinia equina: http://www.facebook.com/photo.php?fbid=10150902996844065&set=oa.387114391301613&type=1&theater Not really enough spots for A. fragacea ???

Andy Horton This particular anemone got be hooked on needing to takes its portrait: http://www.glaucus.org.uk/Fragacea-2.jpg It was kept in captivity for over 12 years. Despite its pale tentacles it it its full complement of spots typical of Actinia fragacea. Unlike the normal Beadlets, it showed no sign of reproducing over all those years. I lost it to a Tompot Blenny which I did not know ate sea anemones at the time.

Becky Hitchin Simply from field observations, I'd say that fragacea are generally larger than equina, lower on the shore and more often in damp / wet places. But that's just ecological preferences.

Andy Horton I find that my field observations from Sussex that red, green or brown specimens are often found together. In captivity they can change colour over a period of weeks or months. Only brown or red specimens get green spots. The largest specimens are found on lower shore mussel beds, but not on all of them.

Jon Chamberlain I was very excited to "discover" Actinia fragacea in Eyemouth, only for Dawn to correct me that it was just Sagartia elegans (which is red and spotted when closed up). It just shows how important a good IDing network is to double check sightings. http://www.flickr.com/photos/underwaterinferno/8088015887/in/set-72157631770525541

Becky Hitchin Jon Chamberlain, I just did the same with a "strawberry" in Cove Bay ...

Message posted on NE Atlantic Cnidaria on 16 Oct 2012
Andy Horton These two sea anemones are having a fight. Anemonia viridis and Actinia equina.

Andy Horton Actinia equina displays aggressive behaviour towards neighbouring individuals. This aggressive behaviour is stimulated when the tentacles of adjacent anemones come into contact. The aggressor stings the victim with nematocysts, in the acrorhagi, which leads to the victim either crawling away or dropping off the substratum. The strawberry anemone, Actinia fragacea, is more plump than Actinia equina and is red to reddish brown in colour with greenish spots (Manuel, 1988). http://www.marlin.ac.uk/speciesinformation.php?speciesID=2359

Andy Horton Note the first use of scientific names in this case. However, in these two species the name Snakelocks and Beadlet are commonly used (English language). The pronunciation of the species name for Actinia varies.

Bernard Picton Gosse's names are OK, but inventing new ones isn't a good idea in my opinion. Ask any European if they've seen any glaucous pimplets recently and you'll get a blank look. QED.

Andy Horton The trend would seem more likely the removal of unsuitable common names. They cause more problems than scientific names.

Message posted on NE Atlantic Cnidaria on 06 Feb 2012
Andy Horton Strawberry type Beadlet Anemone and juvenile Grey Mullet. This is a test posting because of faults.

Andy Horton This photograph was taken circa 1980 (Test message, again)

Andy Horton Is the species Actinia fragacea (if it is a good species?) or the strawberry type of Beadlet Anemone, Actinia equina, found in Norwegian seas?

Fabrizio Frixa Actinia equina Tomato sea Area MarinaProtetta Cyclops Island Acicastello (CT) Depth 0.5 m

Message posted on Scubashooters.net on 02 Nov 2013
Fabrizio Frixa Actinia equina Tomato sea Area MarinaProtetta Cyclops Island Acicastello (CT) Depth 0.5 m

Message posted on UWphotographers on 02 Nov 2013
Fabrizio Frixa Actinia equina Tomato sea Area MarinaProtetta Cyclops Island Acicastello (CT) Depth 0.5 m

Stuart Pearce Very nice shot :)

Antonio Colacino NIce shot (I like "tomato sea" :) ) Italian common name is "Pomodoro di mare" that means "Sea tomato".

Ernst Andres Very nice :-)

Galina Maslova Nice

Annie Bodar superbe merci

Marie-therese Bertin splendide!!!

Message posted on The Global Diving Community on 02 Nov 2013
Rachel Shucksmith Hi this anemone is from North Rona, Scotland at a depth of 20m. This anemone was relatively common. Is it just a beadlet anemone? The column was smooth no warts.

Andy Horton My inclination is to suspect this is Urticina rather than Actinia. I cannot be sure from the photograph.

Wilfried Bay-Nouailhat It's deep 20 meters, but with the blue mark on the mouth and around the foot I rather think of Actinia equina

Rachel Shucksmith Hi Wilfried Bay-Nouailhat, I have a photo of another individual and it also has the blue marks on its mouth. The only thing at these isles/ rocks is that they are likely to be subject to 10m waves in the winter, even in the summer in perfect conditions there was a little bit of a washing machine effect at 15m.

Wilfried Bay-Nouailhat yes, this species lives in hard conditions often in exposed areas.

Andy Horton At what depth (below Chart Datum) is Actinia equina found do you know? It could very well be this species.

Claire Goodwin Urticina eques? but unusual to get one all in one colour like this. How big was it?

Andy Horton I have seen lots of Urticina in one colour at the Dove Laboratory. Not red though. I have changed my mind and gone for Beadlet. I think it might be in an area of strong currents?

Wilfried Bay-Nouailhat Yes, No doubt, it is Actinia equina

Rachel Shucksmith Hi Claire, they were up to 5cm

Rachel Shucksmith Hi yes strong surge related current, moderate tidal flow.

Claire Goodwin In that case I'd agree with Wilfred.

Andy Horton If there are lots of them the same colour it makes it 100% Actinia equina.

Bernard Picton Rachel, look at the top of the column, just below the tentacles. Actinia has large warts, called acrorhagi, which it uses to fight any other anemones which get too close.

Andy Horton http://www.glaucus.org.uk/Beadlet.htm

Message posted on NE Atlantic Cnidaria on 05 Aug 2013
Andy Horton What species would you call this one?

Christian Skauge Dunno... can't see it ;-)

Mary Restell nor me - bizarre. I saw it on notification email but have already deleted it so can't say if its Sagartia elegans or Actinothoe sphyrodeta. What was it?

Christian Skauge It's just his privacy settings I think :-)

Erling Svensen Actinia equina - called Hesteaktinie in norwegian, is very common in Norway. I have not heard about A. fragacea if it not have changed name?

Andy Horton http://www.glaucus.org.uk/fragacea.htm

Andy Horton 3 votes to 1 says this is a separate species to Actinia equina.

Message posted on NE Atlantic Cnidaria on 16 Jan 2013
Taxonomy
Animalia (Kingdom)
  Cnidaria (Phylum)
    Anthozoa (Class)
      Hexacorallia (Subclass)
        Actiniaria (Order)
          Nyantheae (Suborder)
            Thenaria (Infraorder)
              Endomyaria (Superfamily)
                Actiniidae (Family)
                  Actinia (Genus)
                    Actinia equina (Species)
Associated Species