Gracilaria vermiculophylla Ohmi

Also known as Agarophyton vermiculophyllum (Ohmi) Gurgel, J.N.Norris et Fredericq and Gracilaria asiatica Zhang & B.M.Xia.

Common names: Worm Wart Weed
Description: Cartilaginous, dark red or red-brown to almost black (lighter in colour if sun-bleached). Branched fronds are elongated and slender, growing to around 2 m in length but most common 10-30 cm. Branches irregular, terete to slightly compressed in cross-section, often wrinkled with longitudinal grooves, lower parts may be hollow. Holdfast is a small disc.
Habitat: Found in sheltered, shallow habitats. Favours soft-bottomed, muddy, sheltered bays, inlets, harbours, lagoons and estuaries rich with nutrients. Tolerant of many stresses. Most commonly found loose-lying or attached to small stones or shells. Biomass peaks during early to mid-summer.
Distribution: Oriignally described from Japan. Native to east Asia (China, Japan, Korea, Russia) and Vietnam. Introduced to NE (Scandinavia south to Spain) and W Atlantic, W Mediterranean.
Simiar species: Gracilaria gracilis, which test to be less branched, and not compressed and most commonly found on sandy rocks on wave-exposed shores. Expert help is required for certain identification.

Identification guide for selected marine non-native species (National Museum Wales). (Download free PDF, about 3.5 Mb).

Images: © David Fenwick