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An American lobster
standing guard
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It's shy, nocturnal, and armed to the teeth. And it's a popular delicacy on many a seaside diner's plate.

Lobsters (Homarus americanus) are found throughout the Gulf of Maine, both out at sea and near the coast. They are one of the highest value commercial species fished for in Gulf of Maine states and provinces. Once considered a trash fish, suitable only for indentured servants, lobsters are now coveted as a delicacy.

young lobster next to a dime for size comparison
Adult American lobster

We've learned much about the life of this popular crustacean. Lobsters take approximately 6 to 8 years to reach marketable size. They reproduce along all of the states and provinces in the Gulf of Maine, producing eggs each summer when water temperatures reach 56 degrees °F or higher. As many as 12,000 eggs are fertilized as they are extruded onto the females stomach. Here they sit in a tight bundle until they hatch 9-10 months later.

As larvae, lobsters travel great distances. Once hatched, the tiny larvae feed and swim vertically for 30-50 days in the water, carried by currents in a generally counter-clockwise direction around the Gulf. After this stage, the larvae settle down to become bottom dwelling (benthic) lobsters.

adult lobster on a cobble bottom
Young (benthic) lobster with dime for scale

Lobsters prefer to settle in rocky or cobble beds along the coast, mostly below the lowest tides. They are looking for protection from predators such as small coastal fish, crabs, and even other lobsters. They in turn feed on even smaller animal prey for their diet. If conditions are right, a young lobster may remain in a particular cove or rocky embayment for 6 years or longer. Most remain within a few kilometers until they reach sexual maturity. Mature lobsters are not known to be picky eaters. They use their claws to crack open the shells of snails and bivalves, and will readily nibble on either algae or remains of dead animals.

adult lobster in a safe hiding place
The Johnson Sea-Link, a manned submersible from the Harbor Branch Oceanographic Institution, assists in lobster study.

A lobster will shed its shell, known as "molting," generally once each summer, less often as it becomes larger. As its new shell is bigger than the previous one, the lobster swells its tissues with water to fill the space. These lobsters are known as "shedders" when caught. The new shell takes months to complete the hardening process. A lobster may molt up to 25 times in seven years before reaching harvestable size. Interestingly, even at harvestable size, only 10% or so will have reached sexual maturity and reproduced.

It may seem odd, but mature lobsters generally migrate out to sea in the winter time, away from the coast. This is because the open ocean water stays relatively warmer than shallow bays along the coast.

lobster boat at anchor with buoys in foreground

For more than a century, lobsters have been caught in simple traps, sometimes called "pots" after the conical traps of past days. A modern lobster trap is a two-chambered rectangle, once made of wood, now made of coated wire. In one section of the trap lies the bait bag - a mesh bag filled with herring or other fish. The lobster is attracted to the trap by the chemical "scent" of this bait. Lobsters enter through a mesh opening, arriving in the "kitchen" or first compartment of the trap. At this point, it may still find its way back out of the trap.

If, however, the lobster enters the second compartment, it will pass through another mesh opening, wider at its mouth than at its exit. Once through and in the "parlor" or "bedroom" as the second section of the trap is called, the lobster is trapped. Only undersized juveniles can make their way out of this section via an "escape vent."

lobster boat at anchor with buoys in foreground
A scientist measures adult lobsters to determine growth rates.

Underwater video by University of New Hampshire scientists shows that lobsters may enter and leave the first section of a trap repeatedly before finally venturing in to the "parlor."

Female lobsters have long been protected by lobstermen. In addition, it is illegal to harvest an egg-bearing lobster. By convention, lobstermen in Maine will put a V-notch in the tail flipper of a female lobster bearing eggs. This V-notch alerts other lobstermen that they have landed a female that should not be kept or sold. Through natural processes and such simple conservation measures, the lobster population in the Gulf of Maine has increased significantly.

lobster boat at anchor with buoys in foreground
Working lobster boat in Penobscot Bay, Maine

With an annual value of over $186,000,000 in 2000 and almost a quarter of all harvesting licenses dedicated to lobstermen in 2001, fishermen and scientists have both been very interested in patterns of lobster distribution along the shore. For years many people thought that abundant coastal lobsters were the offspring of large "brood" lobsters who live in the deeper waters of the Gulf and do not migrate to shore each spring. However, recent studies suggest that there may be no distinct population of brood stock seeding coastal areas. Studies are ongoing.


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How do you catch a lobster? Click here to find out.
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Penobscot Bay in 3D
Click on the map above to explore the journey area.
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Related information: 
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All About Lobsters
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The Lobster Conservancy
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Click here to see a movie
of lobsters in action

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Downeast, lobster hauls are up big.
Read more
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How do you catch a lobster?
Read more
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Special Thanks: 
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Eric Waterman, Nate Atwell, and
Shaun & Thomas McLennan
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Images and Video ©Bill Curtsinger,
All Rights Reserved
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