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Mediterranean invasive species factsheet

MOLLUSCS

Reproduction Common name: Spotted Sea hare

identification Body light coloured;
characteristic ring patterns

Scientific Name:
Aplysia dactylomela
Picture

Key identifying features

A large sea slug without an external shell. The body is Brief history
smooth and soft, pale greenish yellow with
conspicuous black rings, sometimes pink due to the
ingestion of red algae. A pair of wings covers the
dorsal part of its body and hides a thin shell that can
easily be felt by touch. They also hide a small aperture
to the animal’s gill. Average adult size is 10 cm,
although they can reach up to 40 cm in length. The
head bears 4 soft horn-like structures, two of them like
long ears originating on the dorsal part of the head
(which is why the animal resembles a hare) and the
other two, similar in shape, near the mouth.

Field identification signs and habitat
It occurs on both rocky shores and sand with dense
algal cover, especially in very shallow waters like rock
pools, to a maximum depth of 40 m. It is an herbivorous
species, grazing preferably on green algae.

During the day it hides under large rocks or in
crevices. At night, it is usually seen either crawling like
an ordinary sea slug on seaweeds, or swimming by
undulating the wings in a very characteristic slow,
rhythmic, elegant motion. If disturbed or handled, it
Aplysia dactylomela. Photo: A. Lodola
can release a purple ink or pale malodorous mucus.

Aplysia dactylomela. Photo: E. Azzurro

Monitoring Marine Invasive Species in Mediterranean MPAs: A strategy and practical guide for managers 57