Where are decapod shrimps, lobsters, crayfish, and hermit crabs most common?

Decapod crustaceans, which include shrimps, lobsters, crayfish, and hermit crabs, exhibit diverse distribution patterns depending on their specific group:

• General Distribution: While decapods are primarily marine animals and are most abundant in warm, shallow tropical waters, they have successfully colonized a variety of environments globally.12
• Marine Shallows: Tropical and temperate marine shallows are dominated by ancient palinurans, modern brachyuran (10-legged) crabs, and dendrobrachiate and stenopodid shrimps.1
• Cold and Deep Waters: Decapod caridean shrimps, astacidean lobsters, and anomurans (including hermit crabs) are most common in cold-water and polar regions, as well as in the deep sea.1
• Freshwater and Terrestrial: Approximately 10 percent of decapod species occur in freshwater or terrestrial habitats. Crayfish are found almost exclusively in fresh water, such as streams and lakes, with over half of the known species occurring in North America. Some hermit crabs and other decapods have adapted to terrestrial environments, though they typically must return to the sea to spawn.234