Oysters: they produce the pearls we use for jewelry, and they’re often served in restaurants. Would you guess that these rough, hard-shelled molluscs are also one of the most important species in their ecosystem? Their role as a keystone species comes in the habitat their shells create as they form along flat surfaces, providing homes for hundreds of anemones, barnacle and other small creatures.
Another important function the oyster serves is as a filter. Oysters have gills, similar to a fish, and they eat by pulling water over their gills to trap plankton and particles in their mucus. This same process has the effect of pulling excess nutrients out of the water, making it healthier for other aquatic inhabitants. An oyster can filter up to 1.3 gallons (5 liters) of water an hour, making them one of the most efficient cleaners in the ocean.
You can catch oysters in action in saltwater or brackish habitats, where they form large beds in shallow water. You might see more than oysters in your observations: remember those animals that live on oyster shells? In addition to anemones and barnacles, you could also run across the striped bass, black drum, and croakers that feed on them, or the crabs, sea birds, and sea stars that like to feed on the oysters themselves. There’s a lot to see out there!