Page 59 - Invasive_Species_2013

Mediterranean invasive species factsheet

Similar species Ecological impacts
The most similar jellyfish is the native Mediterranean The nomad jellyfish is a voracious predator that
Rhizostoma pulmo. It differs from Rhopilema consumes vast amounts of shrimp, mollusc and fish
nomadica in its smooth bell surface and a dark purple larvae, and can cause major trophic cascades in the
band around its undulated margin. It has four pairs of marine food web, with a resulting impact on
very large mouth arms on its under surface but no biodiversity.
tentacles.

Another common native species is Pelagia noctiluca. Economic impacts
It is much smaller and mushroom-shaped, with a bell This jellyfish can inflict painful injuries to bathers and
up to 10 cm in diameter. The medusa varies from affect coastal tourism. Furthermore, large swarms
pale red to mauve-brown or purple in colour and the can clog fishing nets, consequently reducing
bell surface is covered in pink granules. It has eight
catches, and block cooling water intakes of coastal
tentacles, pink in colour. The mouth arms can be 5
industrial facilities and desalination plants.
times the bell height.
Pink dots
Management options
Eradication may be impossible in practice. Public
awareness campaigns to alert authorities, first-aid
workers and the general public might prevent injuries
caused by this species.

Scalloped Further reading
purple margin
Deidun A., Arrigo S., Piraino, S. 2011. The westernmost
record of Rhopilema nomadica (Galil, 1990) in the
Mediterranean – off the Maltese Islands. Aquatic Invasions
Vol 6, Supplement 1: S99–S103.
http://www.europe-aliens.org/pdf/Rhopilema_nomadica.pdf
Rhizostoma pulmo Pelagia noctiluca

Rhizostoma pulmo. Photo: Biologiamarina.org

Brief history of its introduction and
pathways
Originally from East Africa and the Red Sea, R. Pelagia noctiluca. Photo: H. Hillewaert
nomadica entered the Mediterranean through the
Suez Canal, and spread with the currents along the
Mediterranean coasts. Since the mid-1980s large Drawings: Juan Varela
swarms of this species have appeared along the
coasts of the Levant every year, from Egypt to
Turkey.

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