NEFSC FishFAQ

Lobster FAQs

A Lobster's Life and Biology

Juvenile lobster, just over a half-inch long
American lobster American lobster
spiny lobster Spiny lobster

Two kinds of lobster-like crustaceans exist in United States waters. The "true" lobster (the American lobster) is designated as such to differentiate it from the other form found here, the spiny lobster. The two, from different families, display two differences:

1. The true lobster has claws on the first four legs, lacking in the spiny lobster;
2. The spiny lobster has a pair of horns above the eyes, lacking in the true lobster.

To avoid confusion over common names, it is best to call the true lobster the "American lobster," and the spiny lobster just that.

The item marketed as "lobster tail" usually is a spiny lobster. The spiny lobster is found in warm waters off Florida, in the West Indies, and off southern California.

Record weight for the American lobster is 45 pounds.

The species in each population are identical in all respects.

Inshore lobsters tend to stay in one place, seldom moving more than a mile or so, but deepwater lobsters farther out on the Continental Shelf follow a seasonal migratory pattern shoreward in summer, returning to the Shelf again in the autumn. The record travel so far is 225 miles, covered by a lobster tagged off the Continental Shelf and recovered at Port Jefferson, Long Island, New York.

Colorless. When exposed to oxygen, it develops a bluish color.

The Homarus americanus, The American Lobster, is also known as the Massachusetts lobster, the Maine lobster, the Canadian lobster or the North Atlantic lobster.

Common squat lobster Common squat lobster

The American Lobster is found on the east coast of North America, from Newfoundland to North Carolina. In 1996, more than 70 million pounds of lobsters were landed in the U.S. Approximately 80% of U.S. landings come from Massachusetts, Rhode Island and Maine.

Lobsters usually move around and hunt for food at night. It was once thought that lobsters were scavengers and ate primarily dead things; however, researchers have discovered that lobsters catch mainly fresh food (except for bait) which includes fish, crabs, clams, mussels, sea urchins, and sometimes even other lobsters!

Lobster landings have increased significantly in the last decade; however, the number of traps fished and general efficiency of the fishing industry have also increased. In the Northeast it is one of several fishery resources that is considered to be generally overfished. Fishermen and managers, however, are working together to develop management measures which will help insure adequate egg production to sustain the resource and fishery. Presently major conservation measures include safeguarding lobsters smaller than 3-1/4" carapace length. (Carapace length is measured from the rear of the eye socket to the rear of the main body shell). Any lobster that is smaller in carapace length than 3-1/4" must be returned unharmed to the sea. These lobsters are known as "shorts" or "sub-legals." Egg bearing females are also protected, and if caught, must be placed back in the sea. Lobster traps must have escape vents to allow sublegal size lobsters to exit the trap while it is still on the bottom (they can come in, eat, and leave). Not all "shorts" leave, however, and so the lobsterman must then throw them back when they pull their trap onto the boat. Lobster traps must also have biodegradable escape panels which will create a large opening and neutralize the fishing potential of a lost trap.

Small lobsters (less than 1-1/2" carapace length) hide in and about sea weeds and rocky habitat that provide adequate food and shelter from predators. Adolescent lobsters (1-1/2" to 3- 1/2" CL) dominate coastal habitats and offshore areas. They may exhibit minimal migratory behavior. Larger, more mobile, adult lobsters may inhabit deeper waters and may return seasonally to shallow warmer waters.

A female lobster mates primarily when she is in the soft-shell state right after she has shed her shell (molted). Female lobsters can carry live sperm for up to two years. At any time she may decide to fertilize her 3,000-75,000 eggs. By law, a female lobster carrying eggs must be thrown back if it is caught.

Age and Growth

lobster eggs Late stage American lobster eggs photographed with digital dissecting microscope.
lobster molt Newly molted juvenile American lobster (top) that has shed its old shell (bottom)

Lobsters grow by molting. This is the process in which they struggle out of their old shells while simultaneously absorbing water which expands their body size. This molting, or shell-shedding, occurs about 25 times in the first 5-7 years of life. Following this cycle, the lobster will weigh approximately one pound and reach minimum legal size. A lobster at minimum legal size may then only molt once per year and increase about 15% in length and 40% in weight. No one has yet found a way to determine the exact age of a lobster. However, based on scientific knowledge of body size at age, the maximum age attained may approach 100 years. They can grow to be 3 feet or more in overall body length.

After molting, lobsters will eat voraciously, often devouring their own recently vacated shells. This replenishment of lost calcium hastens the hardening of the new shell which takes about 14-30 days from the actual loss of the old shell.

Between 20 and 30 molts take place before a lobster reaches the one-pound market size.

lobster with eggs Lobster with eggs

A freshly laid lobster egg is the size of the head of a pin (1/16"). A 1-pound female lobster usually carries approximately 8000 eggs. A 9-pound female may carry more than 100,000 eggs. The female lobster carries the eggs inside for 9 to 12 months and then for another 9 to 12 months externally attached to the swimmerets under her tail. When the eggs hatch, the larvae will float near the surface for 4 to 6 weeks. The few that survive will settle to the bottom and continue to develop as baby lobsters. From every 50,000 eggs only 2 lobsters are expected to survive to legal size.

Lobster babies swim at water surface for 25 days. Only one percent make it to the bottom. These young lobsters shed their shells about ten times in their first year. A near-shore lobster has a 90% chance of ending up on someone's dinner plate.

No one knows exactly, but aquarium studies suggest 5 to 7 years.

Lobsters as Food

American lobster

Several days if kept in a cool, moist environment. The lobster is a gill-breather, and moisture is essential to survival.

No. Fresh water is lethal to a lobster. The animal has salty blood and tissue, which require a seawater environment if life is to be maintained.

Tomalley is the lobster's liver. It turns green when cooked and is considered a delicacy.

Coral is the egg mass of a female lobster. Cooking colors the tiny eggs a deep coral or red.

If the lobster is "headed" before or soon after death, the body meat will keep fresh longer. This is because the so-called head includes the thorax, the site of most of the viscera and gills, which spoil much more rapidly than claw or tail meat.

American lobster American lobster

Five, on the average.

The red pigment is the most stable component of the coloring in a lobster shell. The greens and browns which darken the shell in a live lobster are destroyed by cooking.

Upon the death of a lobster the tail loses its elasticity and ability to curl under the body. When plunged into boiling water, a live lobster curls its tail under. It remains in that position during and after cooking.

Lobsters are not poisonous if they die before cooking, but cooking should not be delayed. Many lobsters sold commercially are killed and frozen before cooking. Lobsters and other crustaceans do spoil rapidly after death, which is why many buyers insist on receiving them alive.

Freezing slows deteriorative changes and harmful chemical actions that follow death.

Etcetera

Blue lobster in aquarium tank

"Red as a lobster" is just a tale. Lobsters come in just about every color but red. They can be blue, light yellow, greenish-brown, grey, dusty orange, some calico, and some with spots. However, they all turn red when they hit hot water. The hot water cuts the link between astaxanthin, a red substance contained in the lobster's shell, and protein which in cold water brings out the predominant coloring.

Not yet, but research is underway to develop rearing techniques and to assess the economic feasibility of rearing the American lobster commercially. In the opinion of many scientists working with the American lobster, commercial aquaculture can be achieved in the near future with a sufficient level of effort. Future projections for the culture of the spiny lobster are not, however, optimistic. Unlike the American lobster which has a relatively short larval life (several weeks), the spiny lobster has a larval life of about six or seven months. The technical difficulties presented by the fragile, demanding requirements of the early life stages discount the use of traditional hatchery methods with any degree of success or practicality.

Yes; this is called "reflex amputation" (autotomy). They can discard a limb, which can be a lifesaving phenomenon. Lobsters have the ability to regenerate some of their body parts; for example, the claws, walking legs, and antennae. The fact that lobsters are capable of limb loss and regeneration is indicative of a very primitive nervous system and their differential sensitivity to pain compared to humans or other types of animals. (They can "drop" a claw, etc. and go off like nothing happened. Could you drop an arm or leg like that?).

The teeth of a lobster are in its stomach. The stomach is located a very short distance from the mouth, and the food is actually chewed in the stomach between three grinding surfaces that look like molar surfaces, called the "gastric mill."

Lobsters "smell" their food by using four small antennae on the front of their heads and tiny sensing hairs that cover their bodies. Their sense of smell is so fine that they can sniff out a single amino acid that tags their favorite food.

Large lobster with eggs

The Massachusetts Lobstermen's Association claimed a record when they caught "Big George" in 1974 off Cape Cod. The lobster weighed 37.4 pounds, with a total length of 2.1 feet.

If a lobster gets into a trap first, crabs would not enter the 'parlor' or holding section. This is because if a crab starts up the entry to the parlor, the lobster will make aggressive displays which make the crab back down. Crabs do not keep other crabs out, nor lobsters, so if a crab got in first, lobsters would still come in. In general, crabs are less aggressive than lobsters.

Attempts have been made to do so, but success has been limited. The Canadian government discontinued in mid-1973 a six-year-old experiment in which the lobsters were reared successfully in the waters off British Columbia. The decision to drop the project was evidently dictated by economics.


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Taken in part from “Being a bouillabaisse of fascinating facts about fish: the most-asked questions,” NOAA Magazine, April and July of 1973.

Unless otherwise noted all color artwork is © Ray Troll 2002, © Terry Pyles, colorization 2002. These images may not be utilized in whole or in part by any entity other than NMFS without the express permission of NMFS' Office of Constituent Services and the copyright artist, Ray Troll.

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(File Modified Sep. 19 2017)