By Alex Scott
There is no better way to understand the importance of the animals and plants in our ecosystem, both local and planetary, than by observing them in their natural habitat, whether that’s in the forest or in a desert or on the beach. But in learning about the wonderful natural world around us, it is easy for us to mistake that nature is there for us to touch and play with. We are animals ourselves, but often we take advantage of animals and plants without realizing it, with deadly consequences. This is the problem currently facing animals in tide pools that are being overrun by well-meaning humans.
Common starfish underwater in the Gulf of St. Lawrence (RLS Photo/Shutterstock).
Echinoderms like starfish and sand dollars live in the intertidal zone, or the habitat at the water’s edge. These areas are often rough and chaotic, with sharp rocky edges and huge waves and the ever-changing sea level. Because the animals and plants that live in the intertidal zone have adapted to these unpredictable conditions, it’s easy to think that these life forms are “tough” and can handle anything. This is not the case. Starfish and sand dollars have evolved over millions of years to survive rough waves and low tides; they have not evolved to survive getting picked up by a human who wants to take a photograph. So what really happens when we interact with an animal in a tide pool?
Detail of tube feet of an orange starfish (Raulbaldean/Shutterstock).
Starfish and other echinoderms take in oxygen and release carbon dioxide the same as we do, but with a very different mechanism from our lungs. Instead of a mouth that inhales oxygen from the surroundings, an echinoderm has tube feet and papulae (skin gills) that take in oxygen from water that moves along its skin. At the same time, the water takes away the carbon dioxide that is created. The constant touch and movement of water is essential for this breathing process, called diffusion, to take place. If a starfish is taken out of the water, there is no way for it to absorb new oxygen or dispel carbon dioxide from its body. It will immediately begin suffocating in the open air—just as we would underwater—without the benefit of having lungs to hold in its breath.
Colorful Red cushion sea stars (Oreaster reticulatus) lie on a shallow sandy seafloor off the coast of Belize in the Caribbean Sea. (Ethan Daniels/Shutterstock).
Even if a starfish out of water is lucky enough not to die instantly, there is an intense physical stress on the body that occurs, and even a moment in the open air can cause the starfish to die later because of the trauma inflicted upon it. Additionally, human skin is covered in oils and bacteria that can also poison a creature that is not adapted to such substances. Pulling a starfish off a surface can damage its tube feet permanently, which may affect its ability to cling to rocks and sand in the future.
Three starfish in a tide pool, Rialto Beach, Olympic National Park, Washington (Gleb Tarro/Shutterstock).
So how can we enjoy these animals and raise awareness without inadvertently causing them harm? Look, don’t touch! These animals are most beautiful surrounded by their natural habitat, not in your hands. Take a photo from a safe distance and leave the animals where they are. If you want to collect sand dollars, make sure that you are only picking up the white skeletal remains and not a live creature. You will know if it is alive by observing the moving spines along its surface and its deep colors. Most importantly, remember that you are only a small part of the ecosystem in which you live, and the animals and plants have a right to live undisturbed in that ecosystem just as much as you do. So observe and marvel at these amazing creatures, tell others about them, and then let them be.
Close up of a colorful star fish in a tide pool (Vara I/Shutterstock).
This article appeared in the Beachcombing Magazine January/February 2023 issue.