Page 92 - Invasive_Species_2013

Mediterranean invasive species factsheet

ASCIDIANS

Reproduction Common name: Giant pink ascidian

identification

Scientific Name:
Herdmania momus
Picture

Key identifying features

This is a relatively large, translucent, pink or red- Brief history
coloured ascidian that can grow up to 18 cm in
height; its body size tends to be larger in the
Mediterranean. Generally it has an inflated, spherical
body with two short, cylindrical siphons on the top
and side. Tiny calcareous spicules lie under the
surface of the outer tunic and internal structures. The
gut can sometimes be distinguished through the Reproduction
Reproduction through gamete release takes place in
transparent body, forming a loop enclosing one of the
the Mediterranean when the water temperature is
gonads.
22–25 °C (around June and November). Fertilization
Small giant-pink ascidians (young individuals) have a and larval development occur in the water column,
soft, thin, transparent tunic, while in larger, older and the development of juveniles is relatively rapid.
individuals it is thicker, more opaque and leathery.
Brief history of its introduction and
Field identification signs and habitat pathways
The species is distinguished by its bright red colour, Originally a tropical Indo-West Pacific species, it is
large size, particularly in older individuals, and its also common in the Red Sea, including the Gulf of
Suez and the Suez Canal. It was first recorded in the
distinctive siphons. It is found mostly on smooth
eastern Mediterranean in Israel in 1958, and in
artificial substrates such as breakwaters, jetties and
Cyprus, Turkey and Lebanon since 2000, as it has
artificial reefs down to depths of 20 m. Small
spread along the Levantine coast. Its colonization of
organisms such as algae may be attached to the Mediterranean regions may be aided by transport in
surface, making its identification difficult. ships’ ballast water and fouling.

Herdmania momus. Photo: J. Garrabou

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