American Oceans

American Lobster

The American lobster (Homarus americanus) is a crustacean species found on the Atlantic coast of North America, found from Labrador, Canada to Cape Hatteras.

Large lobster claw

With its giant claws, the American lobster is arguably the world’s most recognizable crustacean, found in restaurants and seafood shops the world over. Scientifically known as Homarus americanus, the American lobster is popular as a food source for humans, making it a vital commodity both economically and environmentally.

The American lobster is also known as Maine lobster, Atlantic lobster, Canadian lobster, true lobster, northern lobster, or Canadian Reds. 

Characteristics & Appearance

Weight & Length

The American lobster is the heaviest crustacean and the heaviest arthropod in the world. An average American lobster weighs between one and nine pounds, which isn’t that shocking. However, they can grow to enormous sizes. The heaviest recorded American lobster weighed a staggering 44 pounds, caught off the coast of Nova Scotia.

Full size American lobster

The average length of an American lobster is 8 to 24 inches. An average male is about 9 inches long. The longest lobsters can reach 25 inches, making them also the longest decapod crustacean in the world.

Physical Characteristics & Color

People recognize American lobsters by the large round claws. Each claw serves a different purpose. One claw has rounded nodules to crush prey, while the other has sharper edges, which help to hold and tear prey.

The other prominent feature of the American lobster is its antennae. Two long antennae sticking out of the front of the lobster’s head. American lobsters use small hairs on their antennae to smell. An American lobster has a keen sense of smell and can detect which direction smells emanate. It helps them find food and mates and warns them of dangerous rivals and predators.

American lobsters, like many crustaceans, have ten swimmerets, or pleopods. Two of them are their giant claws. The rest are used for swimming or crawling along the ocean floor.

American lobsters are red only after they are cooked. In the wild, they are blue-green to reddish-brown. The shells have speckles of yellow, blue and red. In rare instances, American lobsters can be blue, white (albino), yellow or orange and can also have a strange split-color vertically down the middle. These rare sightings are due to genetic mutations. Social media and news outlets often report these rare instances.

Lifespan & Reproduction

Pair of lobsters on shore

American lobsters have an incredibly long lifespan. If they aren’t caught in lobster fishing traps and succumb to predators or disease, American lobsters can live for 100  to 140 years, and they never stop growing. Their lifespan dramatically surpasses that of their relative, the Caribbean spiny lobster, because of water temperature. Sea creatures generally live longer in cold water.

Lobsters molt. That means they shed their hard shell-like exoskeletons as a new one grows underneath. Female lobsters mate soon after molting when their shell is soft. After a courtship, which involves dance, the male will insert sperm into the female’s seminal receptacle with its legs (pleopods). The female will hold the sperm for many months.

When the female releases its eggs, it passes by the sperm, and the eggs get fertilized. The female stores the eggs on its belly for as long as 11 months. When the eggs hatch, the adult female sets them free into the ocean by flipping its tail. The larvae are only ⅓ of an inch long and are susceptible to predators. They look more like swimming shrimp than lobsters.

They often molt and reach a stage where they undergo metamorphosis and resemble tiny adult lobsters and begin living on the ocean floor. They continue to molt and grow, although less frequently and rapidly. Lobsters that are big enough to catch for food have molted as many as 27 times. 


Where Does the American Lobster Live?

American lobsters live in the North Atlantic Ocean, off the east coast of North America. They have a limited range from Labrador, Canada in the north, to North Carolina in the south. However, sightings south of New Jersey are quite rare.

American lobster in its natural habitat

The species prefers shallow, cold water (less than 68F) in depths ranging from 13 to 160 feet and hides out under rocks. They can live in depths of up to 1,500 feet. When they are not mating, lobsters are solitary animals and guard their territory.

Food & Diet

What Does the American Lobster Eat?

American lobsters hunt their prey at night when there are fewer predators. Mainly they scavenge for dead animals on the seafloor. However, American lobsters also use their strong claws to crush marine life with hard shells such as mussels and other mollusks, starfish (echinoderms), and sea worms (polychaetes). 

Star fish on ocean floor

Humans provide an alternate and popular food source for American lobsters, which is herring used in lobster fishing traps. Most lobsters that enter fishing traps eat the bait and escape, enjoying a free lunch. 

Threats & Predators

Human Threats

Humans are American lobsters’ main predators, as they are harvested for food. Lobster is the most valuable fishery in North America. In 2019 fishing fleets pulled 126 million pounds of lobster from the Atlantic, with a $630 million value.

Lobster trap waiting to be set

Plastic pollution in the Atlantic Ocean also has a detrimental impact on lobster populations, as lobster larvae ingest microplastics, leading to lower oxygen consumption rates.

Climate Change & Global Warming

Evidence suggests warming ocean temperatures have led to a condition that causes minerals to accumulate on the lobster’s bodies, which causes them to suffocate and die. Warming oceans also makes lobster more prone to disease and problems with reproduction. Lobsters prefer water that is below 68°F. As they retreat from warmer waters, lobster fishing industries along the United States coast have collapsed. 

American lobsters are slowly moving northward as ocean temperatures rise, particularly in the waters off Maine, which will lead to further economic problems. It’s unknown how ocean acidification due to global warming will affect American lobster populations. There is also evidence that water temperature above 68°F causes respiratory distress in lobsters and makes them more prone to shell disease.


Seal hunting on ocean floor

Besides humans, fish such as flounder and cod, eels, and seals all eat American lobsters. Lobsters are mainly nocturnal and hide from predators under rocks during the day. If confronted by a predator, a lobster will fight aggressively with its claws.

Other Threats

American lobsters are prone to disease and infection. Certain types of bacteria are fatal to lobsters and can cause health issues such as black lesions, lethargy, respiratory problems, and death.

Conservation Status

Open trap with lobster

The American lobster currently enjoys a stable population and is not considered endangered or threatened, despite its rapid migration northward. The lobster fishing industry is highly regulated to ensure a healthy population, with stricter regulations in southern areas where populations are decreasing. 

Lobster fishing crews have minimum and maximum size limits to protect reproductive lobsters from overfishing. Governments also limit the number of lobster fishing permits they issue and limit the number of traps in the water. 

Fishing crews must release a female lobster caught with eggs on its belly. These lobsters are identified with a small V-shaped cut in their tail, which indicates whether the animal is a protected breeding lobster. 

Fun Facts About American Lobsters

  • American lobsters have two urinary bladders in their heads. They use urine to attract mates and alert other lobsters of their whereabouts.
  • American lobsters’ crushing claws can be on the right or the left side, so like humans, lobsters are right or left-handed. 
  • Pregnant lobsters are said to be “in berry” because the eggs attached to their bellies look like raspberries.
  • Only 6 percent of lobsters that enter traps get caught. Most eat the bait and eventually find their way free.
  • As they can live extraordinarily long lives and continue to grow with each passing molt, American lobsters have been mythically described as immortal.
  • American lobsters have three stomachs. The first grinds food with internal teeth, the second digests the food, and the third passes the undigested food.

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