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Mediterranean invasive species factsheet

Similar species Management options
Due to its morphology, C. fragile subsp. fragile could Prevention: Preventing the spread of C. fragile
be mistaken for two other Codium species: the through quarantine measures such as compulsory
native C. vermilara and C. decorticatum, and only isolation protocols for shellfish to be cultured in new
microscopic examination of the utricles, which are regions (the main vector of introduction) and public
only cylindrical in C. fragile, can reveal the education are some of the few ways to ensure it
difference. does not spread further. Eradication: There are a
few options available to manage C. fragile, although
In Codium vermilara, branches frequently bear
with some limitations. Chemical herbicides are not a
simple or forked proliferations and the tips of the
viable control option as they have adverse effects on
utricles are rounded with numerous hairs. Codium
native communities. Mechanical removal techniques
decorticatum is a species with fewer branches that
such as trawling, cutting, and suctioning have been
can reach a height of 1 metre. Its utricles are regular
tried in different areas. They help to reduce the
cylinders, dilated at the tip but without a sharp point.
density of C. fragile temporarily, but these methods
are generally expensive and the populations quickly
rebound to normal densities. Manual removal could
be an alternative, but great care is needed as the
algae readily reproduce from fragments.

Further reading

http://www.europe-aliens.org/pdf/Codium_fragile.pdf
Codium fragile Codium vermilara Codium decorticatum Bridgwood, S., 2010. Codium fragile ssp. fragile (Suringar)
Hariot summary document. 2010. Fisheries Research
Report No. 202. Department of Fisheries, Western
Flask-shaped outer structures (utricles) of Codium fragile
subsp. fragile, C. vermilara and C. decorticatum Australia. 12 p.
C. Rodríguez-Prieto, et al., 2013. Guía de las macroalgas
Brief history of its introduction and y fanerógamas marinas del Mediterráneo Occidental.
pathways Omega, Barcelona. 656 p.
Native to the North Pacific Ocean and Japan, this
subspecies is nowadays widespread, having been
introduced on shellfish for aquaculture, on
recreational boats and on ship hulls. Secondary
introductions are probably from aquaculture farms,
vessels and fouling on fishing nets.

Ecological impacts
The closely packed frond structure of C. fragile traps
sediments, eventually changing the nature of the
substrate. It is a ‘low-lying’ alga, making it difficult for
some large invertebrates and fish to find refuge or
food between the bushy parts of the alga and the
seabed. It also has a profound effect on native
communities, outcompeting other algae and
invertebrates.
Drawings: Juan Varela
Economic impacts
C. fragile also has serious economic implications for
aquaculture industries, as it has been found to
overgrow and smother oyster beds.

44 Monitoring Marine Invasive Species in Mediterranean MPAs: A strategy and practical guide for managers