This sea squirt, which is an invertebrate marine animal, was found on the beach on Feb. 23, at Carter Nature Preserve in Surry. Credit: Courtesy of Aislinn Sarnacki

I plucked a clear, wrinkly, oval object from the rockweed and held it up in the light of the late afternoon sun.

“What do you think they are?” my husband Derek asked as he pulled one out of our dog’s mouth and tossed it into the ocean.

About the size, shape and texture of a date, the mystery object was mostly clear, with a gray-brown tinge. I placed it in the palm of my hand and tilted it back and forth. It was so clear that I could see liquid and air shift inside.

“Some type of seaweed pod?” I guessed.

I’d never seen anything like it, even though I’ve lived in Maine my whole life and have spent plenty of time exploring beaches. As we continued our walk along the shoreline of Carter Nature Preserve in Surry, we found dozens more of the pruny, globular objects scattered throughout heaps of dried seaweed along the high tide mark.

Juno kept trying to eat them, which concerned us a little bit, since we didn’t know what they were.  

We had visited the preserve to enjoy an easy walk on a shockingly warm February day. The temperature had climbed to the 50s. It felt deceptively like spring, but we knew better. The forecast warned of an impending dive back into single-digit temperatures. The day was simply a respite, and we’d resolved to make the most of it.

At the preserve, a network of three trails totalling 1.5 miles traverse a field, forest and the shore of Morgan Bay. The property is owned and managed by the Blue Hill Heritage Trust, which permits leashed dogs on two of the three trails.

That day, we were more interested in the beach than anything else. There, in addition to the mystery blobs, we found numerous oyster, mussel, clam and periwinkle shells. We also inspected the wide variety of rocks and ledges, some of which had warped, stripy patterns that hinted at an ancient geological process.

A quick Google search on my phone provided no clues as to what the mystery blobs were. And since I dislike using technology while outdoors, I quickly gave up my attempt at on-site identification and resolved to conduct more research when I returned home.

That evening, as I sat on the couch with my laptop, I searched through an extensive database of North Atlantic seaweed. It took about an hour. For those of you who know what the mystery blobs are, stop laughing. I know now that the search was futile.

The “blob” wasn’t seaweed. It was an animal. That’s right, I’d been touching an invertebrate creature — and Juno had been eating them. They’re called sea squirts.

BDN Outdoors contributor Aislinn Sarnacki has solved the puzzle of the sea squirts washed up on the beach on Feb. 23 at Carter Nature Preserve in Surry. Credit: Courtesy of Aislinn Sarnacki

How did I figure it out? I posted pictures in the Facebook group “Maine Naturalists,” hoping that at least one of the 1,200 nature lovers in the group could identify the object. In a matter of minutes, they came through with an answer.

Sea squirts, also known as tunicates, are small marine creatures that siphon water and — you guessed it — will squirt that water when touched or alarmed. An article by Linda Cole for the Smithsonian contains a lot of interesting facts about the creatures. There are about 3,000 tunicate species found in saltwater around the world.

I thought about trying to identify the exact species of sea squirt I had held in Surry. Then I thought better of it. I don’t like my odds of getting it right. But I will say that some of the sea squirts we see in Maine are referred to as “sea grapes,” which seems like the perfect name to me.

Sea squirts have been growing in numbers in the Gulf of Maine in recent years, according to a 2018 Bangor Daily News article. Unfortunately, some of them are considered invasive and can really muck up lobster traps and other fishing gear. There’s concern that they’ll push out local marine species.

One thing that shocked me about sea squirts is how complex they are. In fact, they’re our closest invertebrate relative, according to the Smithsonian. Sea squirts have a mouth, ear, eye, brain, gills, intestine and stomach.

During their larval stage, sea squirts resemble tadpoles and can swim. They then attach to rocks, seaweed or another immobile object (such as lobster traps, unfortunately) before transforming into their adult form.

I’m still not sure if Juno should have been eating them, but it was reassuring to learn that in Mediterranean, Asian and South American countries, certain sea squirt species have been incorporated into local cuisine. On the other hand, some species are considered toxic for humans to eat, so you can never be too careful.

And, since sea squirts act as ocean purifiers, consuming things like bacteria and heavy metals, it seems to me that should be taken into account before eating them as well.

The experience reminded me of the complexity of the wilderness. Even in my home state, I’m often baffled by flora and fauna that I’ve never seen before — and that will probably continue to be the case for the rest of my life. All it takes is a little observation and curiosity while outdoors, and you’re bound to stumble on something you don’t recognize.


Aislinn Sarnacki

Aislinn Sarnacki is a Maine outdoors writer and the author of three Maine hiking guidebooks including “Family Friendly Hikes in Maine.” Find her on Twitter and Facebook @1minhikegirl. You can also...