Overview

The American lobster (Homarus americanus) is a large marine crustacean native to the northwest Atlantic. It is an ecologically and economically important species, widely harvested for food. For general species information see Homarus americanus.

Physical characteristics

Adults have a robust segmented body, a muscular tail, and five pairs of walking legs; the first pair form the distinctive large claws. Those claws are asymmetric in most individuals: one is a broad "crusher" used to break shells, the other a narrower "cutter" or "pincer" used for tearing. Lobsters vary in color—most are mottled brown-green in life, and the pigment changes when cooked—but genetic mutations can produce rare blue, yellow, or calico specimens.

Distribution and habitat

American lobsters inhabit cold to temperate continental shelf waters of the Atlantic Ocean. They range along the east coast of North America from the Gulf of St. Lawrence south to the mid-Atlantic states, favoring rocky bottoms, ledges, and eelgrass where they shelter in crevices. Regional populations and seasonality affect when and where they are most abundant; see range summaries at Atlantic Ocean resources and regional details at east coast guides.

Life cycle and behavior

Reproduction includes internal fertilization and females carry fertilized eggs under the tail until they hatch. Early larvae are planktonic and undergo several molts before settling to the bottom as juvenile lobsters. Growth continues through periodic molting; because growth and survival depend on shelter and food, juvenile habitat is crucial. Lobsters are omnivorous and opportunistic feeders, preying on mollusks, crustaceans and scavenging carrion. Predators include large fish, seals, and octopuses.

Fisheries, uses, and management

American lobster supports a major commercial fishery that uses baited traps (pots). It is a cornerstone of coastal economies in parts of northeastern North America. Management measures—size limits, trap limits, protected egg-bearing females, and seasonal closures—aim to sustain populations and fishery yields. Issues affecting stocks include overfishing in some areas, habitat change, disease, and shifts in distribution related to warming waters.

Notable facts and conservation challenges

  • Lobsters can live for several decades in the wild; age estimates are imprecise because growth varies with environment.
  • Shell disease and changing ocean conditions are monitoring priorities for managers and researchers.
  • Because of its cultural and economic importance, the species is the focus of conservation, aquaculture research, and seafood certification programs.

Understanding biology, fishery practices, and environmental change is essential to maintain healthy lobster populations and the coastal communities that depend on them.