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:
The true lobster has claws on the first four legs, lacking in the spiny
lobster; 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.
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.