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American Lobster (Homarus americanus)

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American Lobster Image

Juvenile American lobster in a New Hampshire tide pool

Jennifer Kennedy, licensed to About.com

Some think of lobster as a bright red delicacy served up with a side of butter. But the American lobster (often called the Maine lobster), while a popular seafood, is also a fascinating animal with a complex life. Lobsters have been described as aggressive, territorial, and cannibalistic, but you may be surprised to know they've also been referred to as "tender lovers".

The American lobster (Homarus americanus) is one of about 75 species of lobsters worldwide. The American lobster is a "clawed" lobster, versus the "spiny," clawless lobster that is common in warmer waters. The American lobster is a well-known marine species and is easily recognizable from its two hefty claws down to its fan-like tail.

Appearance:

American lobsters are generally a reddish-brown or greenish color, although there are occasionally unusual colors, including blue, yellow, orange or even white. American lobsters can be up to 3 feet long and weigh up to 40 pounds.

Lobsters have a hard carapace. The shell does not grow, so the only way the lobster can increase its size is by molting, a vulnerable time in which it hides, "shrinks" and withdraws from its shell, and then its new shell hardens over a couple months. One very noticeable feature of the lobster is its very strong tail, which it can use to propel itself backwards.

Lobsters can be very aggressive animals, and fight with other lobsters for shelter, food and mates. Lobsters are highly territorial and establish a hierarchy of dominance within the community of lobsters that live around them.

Classification:

  • Kingdom: Animalia
  • Phylum: Arthropoda
  • SuperClass: Crustacea
  • Class: Malacostraca
  • Order: Decapoda
  • Family: Nephropidae
  • Genus: Homarus
  • Species: americanus

American lobsters are in the phylum Arthropoda, which means they are related to insects, shrimp, crabs and barnacles. Arthropods have jointed appendages and a hard exoskeleton (outer shell).

Feeding:

Lobsters were once thought to be scavengers, but recent studies have revealed a preference for live prey, including fish, crustaceans and mollusks. Lobsters have two claws - a larger "crusher" claw, and a smaller "ripper" claw (also known as the cutter, pincher, or seizer claw). Males have larger claws than females of the same size.

Reproduction and Life Cycle:

Mating occurs after the female molts. Lobsters display a complex courtship/mating ritual, in which the female picks a male to mate with and approaches his cave-like shelter, where she produces a pheromone and wafts it in his direction. The male and female then engage in a "boxing" ritual, and the female enters the male's den, where she eventually molts and they mate before the female's new shell hardens. For detailed descriptions of a lobster's mating ritual, see the Lobster Conservancy or the Gulf of Maine Research Institute.

The female carries 7,000-80,000 eggs under her abdomen for 9-11 months before larvae are hatched. The larvae have three planktonic stages during which they are found at the water's surface, and then they settle to the bottom where they remain for the rest of their lives.

Lobsters reach adulthood after 5-8 years, but it takes about 6-7 years for a lobster to reach the edible size of 1 pound. It is thought that American lobsters can live for 50-100 years or more.

Habitat and Distribution:

The American lobster is found in the North Atlantic Ocean from Labrador, Canada, to North Carolina. Lobsters can be found both in coastal areas and offshore along the continental shelf.

Some lobsters may migrate from offshore areas during the winter and spring to inshore areas during the summer and fall, while others are "long-shore" migrants, traveling up and down the coast. According to the University of New Hampshire, one of these migrants traveled 398 nautical miles (458 miles) over 3 1/2 years.

Lobster History:

Some accounts, such as that in Mark Kurlansky's book Cod say that early New Englanders did not want to eat lobsters, even though "the waters were so rich in lobsters that they were literally crawling out of the sea and piling up inhospitably on the beaches." (p. 69)

It was said that lobsters were considered a food fit only for poor. Evidently New Englanders eventually developed a taste for it.

Lobsters Today

The lobster's biggest predator is humans, who have seen lobster as a luxury food item for years. Lobstering has increased greatly over the last 50 years. According to the Atlantic States Marine Fisheries Commission, lobster landings increased from 25 million pounds in the 1940's and 1950's to 88 million pounds in 2005. Lobster populations are considered stable throughout much of New England, but there has been a decrease in catch in Southern New England.

In addition to harvesting, lobsters are threatened by pollutants in the water, which can accumulate in their tissues. Lobsters in highly-populated coastal areas are also prone to shell rot or shell burn disease, which results in dark holes burned into the shell.

Coastal areas are important nursery areas for young lobsters, and young lobsters could be affected as the coast is developed more heavily and population, pollution and sewage runoff increases.

Sources

  1. About.com
  2. Education
  3. Marine Life
  4. Marine Life Profiles
  5. Invertebrates
  6. American Lobster - Homarus americanus - Profile of American Lobster

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