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How to Measure a Lobster

Saltwater Marine Fishing Regulations Massachusetts Saltwater Fishing

The Rules

Lobsters must be measured with a special gauge to make sure that they are keepers. Carapace length is measured from the rear of the eye socket to the rear of the carapace on a line parallel to the center line of the body shell. Make sure the gauge is at the extreme rear of the eye socket below the rostrum or horn. A common error is to measure from the horn located forward of the eye socket, which results in an improper measurement.

All lobsters measuring less than the minimum legal carapace length, or larger than the maximum legal carapace length, must be immediately returned to the waters from which taken.

All lobsters must be measured immediately.

Mutilation

It shall be unlawful to possess any lobster, or part thereof, which is mutilated in a manner which makes accurate measurement impossible.

Correct lobster measurement

The gauge is placed in the rear of the eye socket

Is it Male or Female?

In order to determine the sex of a lobster, you must look at the first pair of appendages under the tail, called swimmerets. They are positioned near the base of the last pair of walking legs. The first pair of swimmerets are hard in the male, and soft and feathery in the female.

All About Lobster

What are they?

Lobsters are ten-legged (decapod) crustaceans. The American lobster is the only species of clawed lobster in the Northwestern Atlantic region.

Where are they?

The American lobster is distributed throughout the Northwest Atlantic from the Straights of Bell Isle, Newfoundland to Cape Hatteras, North Carolina.

They are most abundant in coastal zones at depths of less than 150 ft. (~50 m). The greatest abundance of lobster occurs within the Gulf of Maine — from mid-coast Maine to southwest Nova Scotia.

Growth

American lobster is a long-lived species known to reach more than 40 lb. (18 kg).

Age is unknown because all hard parts are shed and replaced at molting (shedding), leaving no accreting material for age determination. In Massachusetts, shedding typically occurs between June and October.

Lobsters at minimum legal size are generally considered to be between 5 and 7 years of age based on hatchery observations. Maximum age is generally considered to be between 30 and 40 years.

Biology

Fertilized eggs are carried on the female abdomen for a 9 to 12 month period of development prior to hatching.

Female lobsters carry between 1,000 and >100,000 eggs depending on the size of the female.

Hatching typically occurs over a 4 month period from May through September. In Massachusetts we typically see peak hatching from late-June through early-July.

Egg-bearing Females

It is unlawful for any fisherman to take or possess any egg-bearing female lobster or female lobster with the egg mass forcibly removed, at any time.