During low-tide walks this week sand dollars (Dendraster excentricus) have been the dominant life form. Everywhere dotting the exposed sand were white tests (as in dead shells), soft deep-purple disks (the healthy live ones), and shapely sand traces (from under-sand burrowing). The feeding must be good and the living easy on this beach. (I just learned that more than 500 individuals can crowd into a square yard!)
Sand dollars are often collected as souvenirs and used in art projects. The white tests are beautiful (although several people collecting the purplish shells didn’t realize these were living animals).
To counter the notion of sand dollars as art, I thought I’d post the art created by sand dollars. Don’t you think their living works are lovelier than those adorning our bureaus and walls?
References & Resources
If you want to learn more about our Pacific coast sand dollar, visit this nicely done San Francisco State biogeography class post from 2005.
Love your photos of these precious specimens. It’s disturbing to hear that folks will collect live ones. It also used to bother me to see kids (and adults) playing with the sea stars. I haven’t had the opportunity to visit any of our beaches at minus tide and wondering if they’ve recovered from the wasting problem they were having?
Thanks. I really like some of the photos, too.
Part of the problem is that many people don’t realize that these animals are alive. I think that’s especially true of intertidal invertebrates, especially those without “faces.” At least that’s what I encountered when I mentioned the difference between the live (purple) and dead (white) sand dollars to those collecting. I think the issue is the same with sea stars (starfish). How could it be alive if it looks just like what you’d find in a curio shop?
Regarding sea star wasting, here’s a link to some of the latest info: http://www.eeb.ucsc.edu/pacificrockyintertidal/data-products/sea-star-wasting/updates.html. It’s my understanding that scientists and observers are seeing some juveniles which means some recovery. But there’s concern about the impact on the ecosystem without the keystone sea stars. So much we don’t know while so much is changing.
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Chris, these photographs are stunning.
Thanks, Jaci. Glad you like them. It was fun playing with the light.
I noticed that you didn’t mention where you specifically walked. I’ve found plenty of sand dollars further south near Morro Bay (http://natureid.blogspot.com/search/label/sand%20dollars), but I rarely see any near home along Monterey Bay. Thanks to my several years of Grunion Greeting volunteer activities, I now know our local beaches are distinctly different and vairable (from Carmel Beach, north through Asilomar, to Monterey Municipal, to Del Monte, then to Seaside Beach. Maybe, instead of full and new moons with highest tides, I should go out @ the quarter moons to find sand dollars? I do not collect, but I do have friends who do. Your capture of movement across sand of sand dollars is awesome!
You’re right about each of our beaches being distinctive. That makes walking them so interesting.
I took most of these photos on morning walks on July 5th and 6th along Del Monte Beach just north of the Del Monte Beach Townhouses. It was a minus tide both mornings. I think the beach “nourishment” that has occurred the past couple of years along this stretch to protect the townhouses may be nourishing the sand dollars. There may also be a season to them — nearly all my photos of sand dollars here have been from June through August.
Thanks for sharing and enjoying our area.