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reproductive success supported by the ability of gametes and zoospores to photo-
synthesize (Beach et al. 1995 ). Furthermore, Ulva species can survive up to
10 months in darkness and are therefore easily transported via ballast water tanks
(Santelices et al. 2002 ).
12.4.7 Undaria pinnatifida
The brown seaweed Undaria pinnatifida , commonly known as “wakame,” is one of
the most commonly eaten seaweeds in Japan. Large-scale commercial cultivation
throughout Asia is primarily for human consumption; however, recently discovered
antiviral compounds offer prospects for further commercial uses (Hemmingson
et al. 2006 ). Invasive biological traits of U. pinnatifida are the very high growth
rate (1-2 cm per day), high reproductive rate, long-range dispersal by floating
reproductive thalli, the capacity for establishing populations in a variety of habitats
and surfaces including artificial substrata, and the ability of gametophytes to
colonize ship hulls (e.g., Casas et al. 2004 ; Thornber et al. 2004 ; Schaffelke et al.
2005 ; Russell et al. 2008 ). Due to the high biomass production and canopy-forming
large blades, U. pinnatifida often outcompetes other algae by shading and space
monopolization; however, ecosystem effects seem to vary greatly between
introduced locations (reviewed in Schaffelke and Hewitt 2007 ).
12.4.8 Codium Fragile Subspecies Tomentosoides
Codium fragile (Suringar) Hariot sensu stricto is an edible green alga, widely
consumed in Korea, China, and Japan. Cultivated in Korea, using seed stock
produced from regeneration of isolated utricles and medullary filaments, the species
is preferred to seaweeds such as Porphyra and Undaria because of its higher market
value (Hwang et al. 2008 ). The protein and amino acid composition in this seaweed
is similar to cereals like wheat, corn, and oats; its high content of minerals, dietary
fiber, and low lipid content make the species a good candidate as a food additive in
human and animal nutrition. In addition, bioactive compounds in Codium fragile
ssp. tomentosoides , including anticancer agents and antibiotics are currently under
investigation (Ortiz et al. 2009 ).
However , Codium fragile ssp. tomentosoides is one of the most invasive
seaweeds, with significant ecological effects ranging from direct competition and
replacement of native species to major changes at the community level (reviewed in
Schaffelke and Hewitt 2007 ). In Chile, the invasive Codium strain competes with
the native agarophyte Gracilaria chilensis causing potentially negative effects to
the coastal economy by threatening the persistence of G. chilensis farms (Neill et al.
2006 ).
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