Aplysia dactylomela
Πληροφορίες
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 can release a purple ink or pale malodorous mucus.
It is hermaphroditic. When mating, one individual acts as a male and crawls onto another one to fertilize it, sometimes forming chains of up to 12 individuals. Eggs form long, tangled strings which may be orange, yellow, green or brown in colour.
Aplysia punctata. Smaller in size, the adults can be confused with young A. dactylomela. The body is not patterned with black rings but only small pink or brown dots.
Aplysia depilans can grow to about 30 cm. It is brown to greenish-brown in colour with blotches of white, yellow or grey, often with blackish veining. When disturbed, it produces both white and purple secretions.
Aplysia dactylomela was first recorded in the Mediterranean Sea off Lampedusa Island in 2002. Now it is widespread throughout the Central-Eastern Mediterranean from Sicily and Malta to Croatia, Greece, Montenegro, Turkey and Cyprus. Its routes of introduction in the Mediterranean are still unclear due to the fact that its native range includes the two seas that are in connection with the Mediterranean basin: the Atlantic and the Red Sea. There are three main hypotheses: 1) it arrived in ballast water (water pumped into and out of ships to adjust their buoyancy; minute marine organisms and their larvae can thus be easily moved around the world’s oceans and introduced into new regions); 2) it spread through the Suez Canal; 3) it spread naturally through the Gibraltar Strait (if this is the case it should not be considered an alien species as such, but a tropical Atlantic species colonizing the Mediterranean through natural range expansion).
To date there have been no studies quantifying the ecosystem impact of this species. However, the species is a grazer of algae and this may influence the composition and diversity of algal communities in a given location.
The giant right neuron of A. dactylomela is very similar to that of humans and is used in neurological research. A small market for A. dactylomela specimens has been created to supply neurological research laboratories with this structure.
Pasternak G., Galil B., 2010. Occurrence of the alien sea hare Aplysia dactylomela Rang, 1828 (Opisthobranchia, Aplysiidae) in Israel. Aquatic Invasions Vol. 5, Issue 4: 437–440.
Yokes M.B., 2006. Aplysia dactylomela: an alien opisthobranch in the Mediterranean. JMBA2 - Biodiversity Records
