Gracilaria

Gracilaria is a genus of red algae (Rhodophyta) notable for its economic importance as an agarophyte, as well as its use as a food for humans and various species of shellfish. Various species within the genus are cultivated among Asia, South America, Africa and Oceania.
Distribution.
"Gracilaria" are found in warm waters throughout the world, though they also occur seasonally in temperate waters. It can not tolerate temperatures below . "Gracilaria" are found in all oceans except the Arctic. Its center of diversity is the Western Pacific, where it has been traditionally cultivated as a source of agar.
Use.
"Gracilaria" is used as a food in Filipino, Hawaiian, Japanese, and Korean cuisines. In Japanese cuisine, it is called "ogonori" or "ogo". In the Philippines, it is called "gulaman" and used to make gelatin. In Jamaica, it is known as "Irish moss". In Korea, it is known as "kkosiraegi".
"Gracilaria" oligosaccharides with degree of polymerization 6 prepared by agarase digestion from agar-bearing "Gracilaria" sp. polysaccharides have been shown to be an effective prophylactic agent during "in vitro" and "in vivo" experiments against Japanese encephalitis viral infection. The sulfated oligosaccharides from "Gracilaria" sp. seem to be promising candidates for further development as antiviral agents.
Aquarium trade.
"Gracilaria" commonly appears as a macroalgae for sale in the aquarium trade. It is a highly palatable algae to tangs and many other herbivorous fish, and its nutrient uptake ability makes it a suitable choice for a refugium.
Ecology.
"Gracilaria" are susceptible to infection by the parasitic oomycete "Pythium porphyrae".