Homarus

Distinguished from Nephrops (scampi/langoustine) by its stout, non-slender body and absence of grooves on claws and abdomen. Separated from Homarinus (Cape lobster) by larger adult size and smooth rather than hairy claws. The two extant species are best distinguished by geography and rostral dentition: H. americanus possesses one or more ventral rostral teeth absent in H. gammarus.

Marine benthic environments from the intertidal zone to depths of approximately 700 m. Occupies rocky substrates, cobble, and mud-sand bottoms where burrows or shelters can be constructed. Juveniles require structured habitat with shelter availability; adults range more widely.

North Atlantic Ocean. H. americanus: western Atlantic from Labrador, Canada to Cape Hatteras, North Carolina, USA. H. gammarus: eastern Atlantic from Arctic Norway south to Morocco, including the British Isles, North Sea, and Mediterranean Sea.

Breeding occurs primarily in summer. Eggs are laid in autumn and carried by females through winter. Larval release occurs in spring, with timing varying by latitude and water temperature. Peak fishery landings often occur in summer and autumn in many regions.

Carnivorous and opportunistic. Prey includes benthic invertebrates such as molluscs (especially bivalves), echinoderms, polychaete worms, and small crustaceans. Scavenges carrion. H. americanus has been documented consuming fish bait in trap fisheries.

Complex life cycle with extended parental investment. Eggs are externally fertilised during laying and carried on female pleopods for 9–12 months. Larval development includes: pre-larva, three zoeal stages (duration 2 weeks to 2 months, temperature-dependent), and post-larval stage. Post-larvae settle to benthic habitat and undergo 3–5 years as juveniles before reaching sexual maturity. Adult moulting frequency decreases with age and size. Generation time approximately 5–8 years.

Males construct and defend mating burrows or shelters. Larger males attract multiple females, creating a polygynous mating system. Females select mates prior to moulting and remain in male shelters during the vulnerable post-moult period. Spermatophores may be stored by females for several years. Adults are primarily nocturnal foragers, remaining in shelters during daylight. Juveniles are more sedentary and shelter-dependent.

Predator and scavenger in benthic marine food webs. Regulates populations of benthic invertebrates, particularly molluscs. Serves as prey for large fish, seals, and other marine predators. Bioturbation through burrowing activity modifies sediment structure and nutrient cycling.

Supports major commercial fisheries in the North Atlantic, with H. americanus representing one of the most valuable single-species fisheries globally. Subject to intensive aquaculture research and limited production. Recreational fishery exists in some regions. Iconic in culinary traditions, particularly in coastal North American and European cuisines.

• Nephrops norvegicusMore slender body with distinct grooves on claws and abdomen; claws are more equal in size without pronounced dimorphism.
• Homarinus capensisSmaller maximum size; claws covered in distinct setae (hairy); restricted to South African waters.

• commercially fished
• claw dimorphism
• North Atlantic
• decapod
• lobster

• BugGuide
• Wikipedia
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life