Codium

Genus of algae

Codium is a genus of edible green macroalgae (or seaweeds) under the order Bryopsidales. The genus name is derived from a Greek word that pertains to the soft texture of its thallus. One of the foremost experts on Codium taxonomy was Paul Claude Silva at the University of California, Berkeley. P. C. Silva was able to describe 36 species for the genus and in honor of his work on Codium,

This genus is the largest member of the algal family Codiaceae and consequently under order Bryopsidales and it currently has about 143 confirmed species and four (4) unresolved members. Stackhouse, unfortunately, failed to provide holotype specimens for C. tomentosum (type species) and some of its dichotomously branching congeners leading to misidentifications; P. C. Silva delineated C. tomentosum, C. fragile, and C. vermilara and established neotypes for each species to finally resolve this taxonomic blunder.

Being a member of the order Bryopsidales, Codium is coenocytic and siphonous. In addition to its thalli variations, the utricles which forms its thallus also has variety of forms, mainly based on their apical wall thickness and apex shapes.

Even though Codium species are well distributed across the globe, certain species have managed to escape their natural range and invade other areas. In the case of C. fragile spp. tomentosoides, commonly known as "oyster thief", the increasing marine traffic has made it possible for it to escape its natural locality (Japan) and spread to Europe and USA forcing devastating biodiversity and aquacultural losses.

Codium has been observed to inhabit both from the intertidal zone down to the subtidal area. Moreover, Codium are also capable of fragmentation, which has led to its unwanted spread across the globe.

South Korea is the leading consumer and producer of farmed Codium (commonly known as cheonggak) in the world; with about 4000 metric tons of fresh weight produced in 2017 and valued at 2 million US dollars. Farming and cultivation of Codium in South Korea is a thriving industry; their method first involves seeding a rope line with isolated pieces of utricles and medullary filaments and finally transferring it into the open sea for the grow out cultivation.

A recent review on the bioactivity of the genus Codium has revealed that most of its polysaccharides, glycoproteins, galactans, anionic macromolecules, and other extracts/compounds have shown to have a variety of uses as immunostimulatory, anticoagulant, anticancer, anti inflammatory, antibacterial, antifungal, and antiviral agent.

Codium is used either fresh or dry and is typically cooked and seasoned with soy sauce and vinegar or mixed with kimchi.