The ocean’s waves moved slowly down the rocky beach, exposing boulders festooned with rockweed and barnacles. My husband, Derek, and I walked along the water’s edge, tossing bits of driftwood for our dog, Juno, to fetch.
I like to think I have a sharp eye for finding the little things in nature, but I think Derek’s is sharper. Time and time again, he has alerted me to interesting plants, mushrooms, rocks, shells and creatures as we wander the outdoors. That day, it was a sea star he found, clinging to rocks just above the water’s edge.
A deep purple-gray with white spines, the sea star was nearly the size of my hand. I picked it up, wondering if it was still alive. To me, it seemed to have a healthy color. It wasn’t bleached out by the sun or stiff from drying out.
When I turned the sea star over, I found a few pebbles were being held by its many tube feet. All of those signs pointed to the creature being alive and well, so I placed it into the water. I don’t know much about sea stars, but I do know that they can dry out if left exposed to the open air for too long.
Since that recent day on the beach, I did a little research about sea stars, and I learned that picking them up is usually frowned upon, especially if you remove them from water to do so. Simply put, sea stars need water to survive. I’ve seen them described as fragile, yet they’ve also adapted to be able to live in the intertidal zone, which alternates between wet and dry, cold and hot.
I’ve been finding sea stars along the Maine coast since I was a little girl. But I didn’t call them sea stars. I called them starfish.
The change came from the scientific community. You see, starfish aren’t fish. They’re invertebrates, closely related to sand dollars and sea urchins. Therefore, it’s thought that “sea star” is a more fitting name. But you won’t catch me correcting people.
A starfish is a sea star, and a sea star is a starfish.
The ocean and a vast, mysterious world: there’s still so much we don’t know about it. To date, scientists have discovered and named nearly 2,000 sea star species worldwide. The Gulf of Maine has only 10, according to an article written by Catherine Schmitt, science communication specialist at the Schoodic Institute at Acadia National Park.
The two most common sea star species in Maine are the Forbes sea star (with the scientific name Asterias forbesi) and the northern sea star (Asterias rubens), which are similar in appearance. Plus there are hybrids of the two species, according to recent research conducted by Melina Giakoumis, a PhD candidate in ecology and evolutionary biology at the City University of New York.
The northern sea star sometimes has prominent lines of spines along its arms, and it has a pale yellow spot called a madreporite near its center. The spot helps the animal take in water and move.
The Forbes sea star, on the other hand, tends to have an orange madreporite. Based on that information, I believe that’s the species Derek recently found on a Mount Desert Island beach. But I can’t be certain.
Other Maine sea stars include the blood star (Henricia leviuscula), horse star (Hippasteria phrygiana), spiny sea star (Crossaster papposus) and purple smooth sun star (Solaster endeca).
Colorful and star-shaped, sea stars are among the most beautiful ocean creatures. They’re a delight to see. But where do you find them?
Sea stars are found all along the coast of Maine. People often find them in shallow, saltwater areas and tide pools, which are pools of water that form between the low and high tide marks. I find it’s best to look for them at low tide, in the shallows just beyond the water’s edge. And I’ve always had more luck finding them in rocky areas rather than sandy or muddy areas.
Sea stars are a keystone species, meaning they have a big impact on the ecosystem they live in. They eat a variety of animals including blue mussels, which form colonies that dominate rocky coastlines. By knocking out some of the mussels, sea stars free up space for other animals to thrive. They also like eating oysters and clams.
Two years ago, the Shaw Institute and Schoodic Institute noticed an unusually high number of sea stars at their research stations in Blue Hill and Winter Harbor. To learn if the phenomenon was widespread, they asked the public to take photos of sea stars along the Maine coast that summer. By the time the project wrapped up, they had received nearly 100 sea star observations.
If you’re interested in learning about animals along the Maine coast, I suggest checking out the book “Life Between the Tides: Marine Plants and Animals of the Northeast,” written by Les Watling, Jill Fegley and John Moring, illustrated by Andrea Sulzer and edited by Susan K. White of the Maine Sea Grant Program.
Also, sea star researcher Giakoumis gave an online presentation about her work that’s available to watch on YouTube. The video is called “Sea Star Research with Melina Giakoumis.”
Next time you visit the Maine coast, I hope you’re lucky enough to stumble upon a sea star. They can be a challenge to find, but that just makes it all the more special.