West Seattle scenes: Can you solve these low-tide mysteries?

Eve sent these two photos taken during Friday’s low-low tide, wondering if anyone knows what they are – the first, she said, looked “like plastic” but clearly wasn’t (we also recall seeing the formation in another low-tide photo we had received but not published); the next, she said, looked almost “like red tide”:

Thanks in advance, beach expert(s) who will solve the mystery!

10:24 PM UPDATE: Thanks to everyone who has solved the FIRST mystery in the comment section – second one is still a open case.

23 Replies to "West Seattle scenes: Can you solve these low-tide mysteries?"

  • bertha June 18, 2011 (10:05 pm)

    The top photo is of moon snail eggs. Don’t know what the bottom one is.

    • WSB June 18, 2011 (10:24 pm)

      Thank you, intrepid mystery-solvers!!!!

  • Joe June 18, 2011 (10:07 pm)

    moon snails make those for their eggs (first picture)

  • Aaron June 18, 2011 (10:08 pm)

    The plastic looking bit is actually sand held together by a resin excreted by the moon snail as protection for its eggs.

  • clark5080 June 18, 2011 (10:10 pm)

    First one is a sand ring from I think moon snail egg casing

  • johnnyblegs June 18, 2011 (10:11 pm)

    I saw these at a low tide last year. My wife and I were wondering the same thing. Plastic like bowls all over the beach. We were told that they were actually sand and they are the product of moon snails. The plastic like ring is their sand collar that protects the eggs. More info here: http://www.dailykos.com/story/2008/10/09/625582/-Marine-Life-Series:-Moon-Snails-and-Sand-Collars
    Scroll down to the bottom of the page and you’ll see the picture of the sand collar.

  • mrsB June 18, 2011 (10:12 pm)

    The plastic-looking sand formation in the first photo is created when a moon snail lays its eggs.

  • clark5080 June 18, 2011 (10:13 pm)

    A link to a closer pic of a sand ring

  • Beach Bum June 18, 2011 (10:17 pm)

    The top photo is of an egg collar laid by what I believe is the moon snail.

  • Bea Sweeney June 18, 2011 (10:20 pm)

    I’m not sure about the second photo, but the first is from a moon snail. We always called it a moon snail collar, but I think it’s an egg case. I’ve never posted photos here, but I have a great one of my granddaughter holding an actual snail as it squeezes itself into its shell, like a giant sponge that starts out as large as a dinner plate and squeezes LOTS of water out and becomes small enough to get into its shell.

  • HunterG June 18, 2011 (10:24 pm)

    The first is a photo of a moon snail’s egg casing.


    The second is unknown to me.

  • Jeff June 18, 2011 (10:25 pm)

    I found this interesting article:


  • Neighborly June 18, 2011 (10:28 pm)

    My guess, for mystery 2 is sea cucumber roe. I observed one releasing its eggs at a Lowman Beach low tide last month, and they were that color.

  • Beth June 18, 2011 (10:50 pm)

    Thank you clark5080. The top one is sand. I have several pictures of them from Vashon Island. Sand. All sand. Very cool, nonetheless.

  • ellenater June 18, 2011 (11:01 pm)

    ha ha. The first time I saw a beach full of moon snail casings, I thought a boat full of car parts had capsized. They look so much like some kind of engine filter.

    What is the SECOND pic. of?

  • Lura Ercolano June 18, 2011 (11:29 pm)

    The second picture appears to be a harmless bloom of noctiluca.

    Here’s an old article: http://community.seattletimes.nwsource.com/archive/?date=19960624&slug=2336090

    About 8 years ago we had lots, and the news helicopters took lots of film, ready to cover some big industrial spill or something, but it’s just a natural little critter. You can scoop some of the water up and look at the little glowing individual creatures.

  • Paul June 19, 2011 (4:12 am)

    Toxic chemicals in our Elliot bay

  • Eve June 19, 2011 (10:12 am)

    Thanks everyone who responded. Now I’m off to check the Internet for more information about moon snails and noctiluca.

  • WSC June 20, 2011 (8:03 am)

    Moon snails are an invasive species that mostly drill and kill clams (native) of various types. Moon snails, while interesting, are better bashed and made scavenger food then left to proliferate.

  • Rhonda Porter June 20, 2011 (5:00 pm)

    WSC, I believe that smashing moon snails is prohibited – at least on the marine preserves and reserves in the area (such as that off of Emma Schmitz View Point).

  • Lura Ercolano June 20, 2011 (11:45 pm)

    WSC, you are mistaken. Our Moon Snail is a native species, NOT an invasive species.
    There are areas in New England on the East Coast where a different kind of moon snail is a problem invasive species, but that does not mean that our snails are invasive or non-native. They belong here.
    Here is our state’s site about invasive species:
    Note that Moon snails are not listed on that site.

    • WSB June 21, 2011 (12:53 am)

      Hey, Lura and any other waterfront folk … let me know if you see the noctiluca glow. I just went out to take a look (past midnight) and there’s too much artificial light over the public waterfront along Beach Drive to tell. Just curious! – TR

  • Ray West June 29, 2011 (7:34 am)

    The Moon snails (Euspira lewisii) that inhabit PNW beaches do eat clams, but they are definitely NOT an invasive species, so please do not destroy any egg collars you find at low tides.

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