Crabs in the rocky intertidal zone
Mud crabs and Asian shore crabs are two of the most common crabs that you’ll find along Long Island Sound’s coastline, specifically in the rocky intertidal zone. This unique habitat lies between the high and low tide lines, meaning it is only accessible by humans and land predators during mid- to low tide.
As the tide recedes, the rocky intertidal zone is exposed to dry air, intense sunlight, and increased predation. Many animals, such as the mud and asian shore crab, must prepare for these challenges. To stay safe, they will seek protection by hiding underneath rocks.
Mud crabs are native to Long Island Sound and are commonly found in oyster reefs or underneath rocks while foraging for algae and decaying organic matter. Asian shore crabs, however, are not native to Long Island Sound. They were introduced to Long Island Sound in 1998 and have become the dominant intertidal crustacean by displacing other native and non-native organisms by as much as 99% (Kraemer, 2012, p. 2).
Asian shore crabs are opportunistic omnivores, eating anything and everything they can get their claws on, from decaying matter to even other crabs. Their broad diet, paired with rapid reproduction (females release 200,000 eggs per year), has significantly disrupted the balance of Long Island Sound’s food web.
Marine ecosystems are open and constantly connected, making it nearly impossible to attempt complete removal of the already established Asian shore crab population from Long Island Sound. However, there are ways we can help restore balance. Many native predators have started to recognize asian shore crabs as a food source, and we can too! By choosing restaurants that serve local and sustainably harvested seafood or participating in citizen science programs that monitor crab populations, we can work together to protect the health of Long Island Sound.
Citations:
