gramandy's picture

Flat Periwinkle eggs

Observed: 27th March 2013 By: gramandy
Kent Wildlife TrustThanet Coast ProjectWildwood Trust
gramandy’s reputation in Invertebratesgramandy’s reputation in Invertebratesgramandy’s reputation in Invertebratesgramandy’s reputation in Invertebrates
Flat Periwinkle eggs

Annual emptying of Thanet's largest tidal pool (at low tide end would be 5m) Found in sublittoral, submerged probably all of the time here, when the sluice gates are shut. Lots of this dotted about on the fucoids but mostly the kelp blades.

Species interactions

No interactions present.


dejayM's picture

Clumps n strings

I have just posted up a picture of periwinkle eggs. They are in quite long strings.
Whatja think?
... "Female common periwinkles release egg capsules, containing two or three eggs, directly into the water during the spring tides."

dejayM's picture

Clumps and strings

OH - goodness, Ignore this.
I wish admin would make it possible to DELETE duplicates!

gramandy's picture

what are you trying to ...

...get at? - Periwinkle eggs are layed in clumps? I'm confused.

dejayM's picture

clumps, strings and capsules

No, no don't be confused but I am.
My posting shows flat periwinkle eggs (I think) in strings. I am assuming that because they and common periwinkles were the only ones present (other than the Dog Whelks).
The reliable Oceana 'quote' though is from the web and mentions capsules - I assume a capsule is NOT a jelly clump..."circular mass"
I am just about to test the water with my strings - I will leave a comment.
Done -

ChrisMcA's picture

Yes, my flat periwinkle (L.

Yes, my flat periwinkle (L. obtusata) suggestion probably a mistake because Dejays are too large. But these arent common periwinkle (L. littorea) eggs as they're shed into sea as tiny capsules of 3 eggs (.96mm across accrdg to Lebours).(Collins & Lebours both agree on this).

dejayM's picture

the debate

Graham - 'we' are fast coming to the conclusion that "Littorina littorea sheds egg capsules directly into the sea." not laying is clumps of jelly.
See here though there are other web references.
My post here
is gathering comments

JoC's picture

Eggs on photomarine and Arkive

Hi Graham, I too saw the imagse you link to. If you look at Nassaruis reticularis on the same site you can see what I think are the same egg type. .It's the penultimate photo in the list.
I believe Arkive has a wrongly labelled picture too, even though their text clearly states the aggs are laid into the sea.


gramandy's picture


...measure for caution I suppose - when there is conflicting evidence :)

Not as straight forward as is first thought, who is the definitive authority on this?

dejayM's picture


yes...this is good stuff isn't it.
I am of the growing opinion that -
a/ marine invertebrates need their own Group
b/ there is a shortage of 'experts' in iSpot

As for your links, how really interesting. I see thousands of common periwinkles on my shore here, at all states of the tide and have yet to see rounded egg-clumps or those delightful cases in the Arkive site.
I am off to the shore in a few minutes and will probably post up some Winkle-stuff later today.
I have always considered the Marlin site to be the 'authority' - but now I'm not so certain.
Thanks for your continuing interest Graham.
Derek (in Orkney)

gramandy's picture

absolutely right..

...if you look at the number of the coastal postings that I have with no agreements, it suggests we lack enough experts in this area - by this area I mean coastal FLORA and FAUNA. What I think are straightforward sightings are quite clearly not to other members of iSpot. Hopefully with the increase of membership, there will be an increase of potential coastal/marine interested people. With numbers comes different experiences and knowledge. I am beginning to experience this with yourself for instance. It's not always easy to catch postings either unless you are a regular visitor. Sometimes it pays to go through marine and coastal to see what you have missed. All postings to me, give an insight into other areas flora and fauna and gives me a better feeling for what I may be seeing. I now have the tendency to talk to the MBA for which I am not sure about. I am also lucky in having a seaweed guru living a few miles down the road - who I visit and discuss pics with. Very often not good enough as you need microscope ID. Glaucus is another posting area with experts on this site.

Bit of an epistle I know, should have saved it for forums really.


dejayM's picture

the time

I imagine you HAVE activated the filter 'Observation that you've commented on' in My Spot.
Without this tick I'd get lost quite quickly.
But not all those little boxes should be ticked though, as otherwise we would never leave the computer!
I've just come back from the shore with a mystery - ah well.... it's nice to have time!

gramandy's picture


...but I'm averse to ticking my agreement ones as there are rather a lot. As you say I've been here too long this morning, have to go and cut a lawn while we have some sun.

dejayM's picture

back to the post...

You'll be pleased (we'll all be pleased) to see here
right near the bottom, that the Flat Periwinkle (Littorina obtusata) appears to lay eggs in small clumps. Yes?
Text here
If so, then perhaps a new ID - Flat Periwinkle Eggs - might draw agreements!

ChrisMcA's picture

Not necessarily.I googled

Not necessarily.I googled Lacuna pallidula eggs & got extracts from "A student's guide to the seashore", which describes their egg masses as round to oval masses,white etc w. 100 or so eggs. &...[they] resemble those of flat periwinkle L.obtusata & L.fabalis but these 2 species' are usually oval to kidney shaped..& w. many more eggs than Lacuna pallidula. The book describes both as favoring Fucus seaweeds (obtusata also ascophyllum).My count on the top of 4 was about 39,& even if some were pairs of eggs still <100.

dejayM's picture


..isn't it a saga, with such a simple thing, Graham.
What we (you) can be fairly certain of, is that these are NOT Common periwinkle - I think the evidence is pretty overwhelming.

Assuming your gut instincts were right, originally, then this should be Flat periwinkle as Pale periwinkle would have occurred to you before, I imagine.

We have millions of Flat p's here, I have yet to find small rounded jelly clumps of eggs on seaweed!

So, as I have been a marine biologist for two whole weeks, I am close to agreeing - may well agree soon. You are not allowed to!
Back-quote here -

dejayM's picture

long story

At last I have agreed and posted my own
But it shore (got it?) is a long story!