Invertebrates

From crabs to octopuses, clams to marine worms, invertebrates play a significant role in ocean ecosystems. Many are important prey for fish, marine mammals, and humans. Others, such as corals and oysters, create essential habitat for marine species.

NOAA Fisheries is responsible for the sustainable management of many species of invertebrates—including white shrimp, Alaska snow crab, and Quahog clam—commonly harvested for human consumption. We are also responsible for protecting invertebrate species listed under the Endangered Species Act such as white abalone and elkhorn coral. 

Invertebrates are the most diverse group of animals in the ocean. Some common marine invertebrates include mollusks, crustaceans, and corals. 

Mollusks are a category of invertebrates with over 50,000 known species. They are soft-bodied animals that may have a hard external shell (formed by secreting calcium carbonate), a hard internal shell, or no shell at all. Mollusks include abalone, conch, oysters, and clams, as well as octopus and squid.

Crustaceans are a subcategory of invertebrates closely related to insects and spiders. They typically have a body covered with a hard shell or crust. Crustaceans include shrimp, krill, lobsters, and crabs.

Corals are known as colonial organisms because many individual creatures live and grow while connected to each other. The tiny, individual organisms that make up large coral colonies are called coral polyps. Stony, shallow-water corals—the kind that build reef habitat—are one type of coral. There are also soft corals and deep sea corals that live in dark, cold waters. Learn more about corals.