American Lobster - Oceana

Cephalopods, Crustaceans, & Other Shellfish

American Lobster

Homarus americanus


Restricted to temperate latitudes of the Northwestern Atlantic Ocean from North Carolina to Labrador


Rocky reefs

Feeding Habits

Foraging predator


Subphylum Crustacea (crabs, shrimps, and relatives), Family Nephropidae (clawed lobsters)


The American lobster has been recorded as heavy as 44 pounds (20 kg), and is the largest crustacean in the world by weight. Along with true crabs, prawns, and other lobsters, the American lobster is a decapod; it has ten legs, and it is covered with a spiny exoskeleton that provides it some protection from potential predators. Most American Lobsters are rusty brown in coloration, but a wide variety of strange colors/patterns have been rarely observed by fishers and scientists. These include individuals that are bright blue, green, mottled, and even some that are perfectly divided down the middle with different colors on each side (e.g., half blue, half black; half black, half red; etc.).

The American lobster’s front legs are modified into very large claws. The two claws are slightly different from each other, with one being stronger and used for crushing while the other is sharper and used for cutting. Like in all decapods, the American lobster’s shell really is a skeleton on the outside of its body. The exoskeleton does not expand, and therefore the lobster must molt it regularly in order to grow bigger. Before molting, an individual begins building a new, larger skeleton inside the existing one. As it gets too big to be contained, it splits open the outer shell, and the new exoskeleton hardens. During this process, the new exoskeleton can be soft for several hours, and the lobster is highly vulnerable to predation.

During the day, American lobsters remain in hiding places along their rocky reef habitats. During the twilight hours and at night, individuals are much more active and forage along the reef for a variety of prey, including many types of invertebrates, decaying organic matter, and some algae. These lobsters will eat most things that they find. Large fishes and octopuses are known to eat adult American lobsters, and a larger variety of fishes eat the juveniles. Unlike many aquatic species, American lobsters reproduce via internal fertilization. After a male passes his sperm to a female, she stores the fertilized eggs on the ventral side of her body until they hatch.

American lobsters support a massive fishery in the northwestern Atlantic Ocean, where several successful management regulations have been applied to ensure that the fishery will continue to be viable into the future. These include size limits, gear limits, and other management techniques. Population status varies by region; however, while the species as a whole might be safe from extinction, it is not stable at an individual population level.

Engage Youth with Sailors for the Sea

Oceana joined forces with Sailors for the Sea, an ocean conservation organization dedicated to educating and engaging the world’s boating community. Sailors for the Sea developed the KELP (Kids Environmental Lesson Plans) program to create the next generation of ocean stewards. Click here or below to download hands-on marine science activities for kids.

Kids Environmental Lesson Plans

Additional Resources:

IUCN Red List

NOAA Fisheries