Commercially-important
Guides
Astacoidea
Northern Hemisphere Crayfishes
Astacoidea is a superfamily of freshwater crayfish restricted to the Northern Hemisphere. It comprises three families: Astacidae (Europe and western North America), Cambaridae (eastern North America), and Cambaroididae (eastern Asia). Members are distinguished from the Southern Hemisphere superfamily Parastacoidea by geographic distribution. Crayfish in this group possess ten walking legs, feather-like gills for respiration, and a segmented body with a hard exoskeleton. Many species construct burrows for shelter, with complexity varying from simple tunnels to elaborate multi-chambered systems.
Callinectes sapidus
blue crab, Atlantic blue crab, Maryland blue crab
Callinectes sapidus is a large portunid crab native to the western Atlantic Ocean and Gulf of Mexico, with established invasive populations in Europe, Asia, and elsewhere via ballast water transport. The species exhibits pronounced sexual dimorphism in abdominal shape and claw coloration. It supports major commercial fisheries, particularly in the Chesapeake Bay and Gulf of Mexico, though populations have declined in some areas due to overfishing and environmental degradation. As an invasive species, it damages fishing gear and competes with native species in introduced ranges.
Caridea
caridean shrimp, true shrimp
Caridea is a species-rich infraorder of decapod crustaceans comprising over 3,000 described species of true shrimp. Members are distinguished from other shrimp groups by their brooding reproductive strategy, lamellar gill structure, and characteristic abdominal segmentation where the second segment overlaps both the first and third. They occupy diverse aquatic habitats from freshwater streams to abyssal depths exceeding 5,000 meters, with roughly one-quarter of species inhabiting freshwater environments. The group includes commercially significant species such as Pandalus borealis and ecologically important cleaner shrimp that maintain reef fish health.
Decapoda
decapods, ten-footed crustaceans
Decapoda is the most species-rich order of Crustacea, with over 14,500 described extant species worldwide. Members include crayfish, crabs, lobsters, prawns, and shrimp—collectively known as decapods or "ten-footed" crustaceans. The order exhibits extraordinary morphological diversity, ranging from tiny symbiotic shrimps under one centimetre to large crabs and lobsters. Decapods occupy virtually every aquatic habitat on Earth, from deep-sea trenches exceeding 5,000 metres depth to terrestrial environments, with nearly half of all species being crabs. The order includes several infraorders with distinct body plans: Brachyura (true crabs), Caridea (shrimps), Anomura (hermit crabs and allies), and others.
Pleuroncodes
red crab, tuna crab, squat lobster, múnida
Pleuroncodes is a genus of anomuran crustaceans (squat lobsters) in the family Munididae, found in the eastern Pacific Ocean. Species occupy both pelagic and benthic habitats depending on life stage, with larvae and small individuals in pelagic waters and larger adults on the seafloor. The genus includes commercially and ecologically important species that form dense aggregations and serve as prey for large marine predators.