Gracilaria vermiculophylla Ohmi
Also known as Agarophyton vermiculophyllum (Ohmi) Gurgel, J.N.Norris & 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. In
Ireland, found in estuarine muddy bays (Clonakilty, Roscarbary,
and probably Blackwater estuary, Dungarvan Bay), often in
conditions of varying salinity.
Distribution: Orignally described from Japan.
Native to east Asia (China, Japan, Korea, Russia) and and SE
Astia (Vietnam). Introduced to NE (Scandinavia south to Spain,
including Britain and Ireland) and W Atlantic, W Mediterranean.
Simiar species:
Gracilaria gracilis, which tends 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.
Links:
Invasion history in North America.
Global Invasive Species Database.
Identification guide for selected marine non-native species (National Museum Wales). (Download free PDF, about 3.5 Mb).
Images: © David Fenwick
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