For centuries, Portunid (swimming) crabs have constituted an important secondary crop in the traditional intertidal fishponds of Asia. The most commonly cultivated crab is Scylla serrata, which is distributed throughout the Indo-West Pacific from eastern South Africa to Hawaii and from northern Australia to southern Japan. It is known as the mud or mangrove crab (Australia), Samoan crab (Hawaii), alimango (Philippines), tsai jim (Taiwan) and nokogiri gazami (Japan). Occasional attempts have been made at pond rearing Portunus pelagicus (sand crab or blue swimmer) and P. trituberculatus (the Japanese blue swimmer or gazami).

Modern hatchery techniques for Portunus are well advanced. P. pelagicus is found over much the same geographic range as Scylla, extending further into colder waters. P. trituberculatus is found in Japan, China, Taiwan and Korea. Important fisheries for all three species exist throughout their areas of distribution.