Page 97 - Invasive_Species_2013

Mediterranean invasive species factsheet

Similar species Caspian Seas it caused the collapse of many fish
The most obvious distinguishing feature is the extent stocks and affected the entire ecosystem,
of the animal´s oral lobes: in M. leidyi, they span transforming pelagic food webs into comb-jelly food
nearly the entire length of the body, while in native webs. Its effects on the Mediterranean are so far
ctenophores and in Bolinopsis vitrea, another alien insignificant, or at least less dramatic.
species, they only reach half-way along the body.
This species has been nominated as one of the 100
Moreover, B. vitrea also lacks papillae (warts) on its
‘World's Worst’ invaders (IUCN, 2005).
body.

Ecological impacts
Invasion by this species has caused significant harm
to small-scale commercial fishing operations by
reducing catches and fouling fishing gear. As it feeds
on zooplankton, it consumes commercially important
fish eggs and larvae and can affect local fish
production, causing total stock depletion.

Blooms affect coastal tourism and can clog the
cooling water intakes of industrial facilities and
desalination plants.

Management options
Short oral lobes
Eradication may be impossible in practice since the
Bolinopsis vitrea species is too widespread in the Mediterranean Sea.
Appropriate regulation of the treatment and/or
exchange of ships’ ballast water may prevent further
Brief history of its introduction and introductions.
pathways
Native to the Atlantic coasts and estuaries of North
and South America, Mnemiopsis leidyi was first Further reading
introduced to the Black Sea via the ballast water of Shiganova T. A. et al, 2001. Population development of the
invader ctenophore Mnemiopsis leidyi, in the Black Sea and in
ships. The Black Sea M. leidyi population spread
other seas of the Mediterranean basin. Marine Biology 139,
into the Sea of Marmara with the currents and 431-445.
thence into the north-western Aegean Sea, where it http://www.europe-aliens.org/pdf/Mnemiopsis_leidyi.pdf
was first recorded in 1990. Soon afterwards, it was
Global Invasive Species Database: Mnemiopsis leidyi
recorded off the Mediterranean coast of Turkey and http://www.issg.org/database/species/ecology.asp?si=95&fr=1&
in Syria. In the mid 2000s it appeared in France and sts=
the northern Adriatic Sea, and nowadays large
blooms of this species are commonly reported in
Israel, Italy and Spain.

Ecosystem impacts
It is a voracious feeder, preying on zooplankton,
pelagic fish eggs and larvae. Large aggregations
can reduce native zooplankton communities, have
negative effects on fish feeding (by competition) and
cause major trophic cascades in the marine food
web, thereby affecting biodiversity. In the Black and

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