Mediterranean invasive species factsheet www.iucn-medmis.org Species report Aplysia dactylomela (Spotted sea hare) AFFILIATION MOLLUSCS SCIENTIFIC NAME AND COMMON NAME REPORTS Aplysia dactylomela 12 Key Identifying Features A large sea slug without an external shell. The body is 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. Identification and Habitat Average adult size is 10 cm, although they can reach up to 40 cm in length. The head bears 4 It occurs on both rocky shores and sand with soft horn-like structures, two of them like long dense algal cover, especially in very shallow ears originating on the dorsal part of the head waters like rock pools, to a maximum depth of 40 (which is why the animal resembles a hare) and m. It is an herbivorous species, grazing the other two, similar in shape, near the mouth. preferably on green algae. 2013-2021 © IUCN Centre for Mediterranean Cooperation. More info: www.iucn-medmis.org Pag. 1/5 Mediterranean invasive species factsheet www.iucn-medmis.org 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. Reproduction 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 History and Route of brown in colour. Introduction Similar Species Aplysia dactylomela was first recorded in the Mediterranean Sea off Lampedusa Island in Aplysia punctata. Smaller in size, the adults can 2002. Now it is widespread throughout the be confused with young A. dactylomela. The body Central-Eastern Mediterranean from Sicily and is not patterned with black rings but only small Malta to Croatia, Greece, Montenegro, Turkey pink or brown dots. and Cyprus. Its routes of introduction in the Mediterranean are still unclear due to the fact Aplysia depilans can grow to about 30 cm. It is that its native range includes the two seas that brown to greenish-brown in colour with blotches are in connection with the Mediterranean basin: of white, yellow or grey, often with blackish the Atlantic and the Red Sea. There are three veining. When disturbed, it produces both white main hypotheses: 1) it arrived in ballast water and purple secretions. (water pumped into and out of ships to adjust their buoyancy; minute marine organisms and Other species that look similar 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). Ecological Impacts 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. 2013-2021 © IUCN Centre for Mediterranean Cooperation. More info: www.iucn-medmis.org Pag. 2/5 Mediterranean invasive species factsheet www.iucn-medmis.org Economic Impacts 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. Management Options There is still no feasible management plan in place for controlling this species. A suggested prevention measure is to build up local public awareness combined with monitoring to help in preventing its introduction into MPAs. Early eradication of new populations by hand removal could be an option to be explored. Further Reading 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 2013-2021 © IUCN Centre for Mediterranean Cooperation. More info: www.iucn-medmis.org Pag. 3/5 Mediterranean invasive species factsheet www.iucn-medmis.org Map of sightings of the species Aplysia dactylomela (Spotted sea hare) Legend Algae Angiosperm Cnidarians Centre for Mediterranean Molluscs Crustaceans Ascidians Cooperation Combjellies / Fishes Ctenophores More Information: Guide and reports platform for Marine Protected Areas (MPAs) in the Mediterranean. www.iucn-medmis.org 2013-2021 © IUCN Centre for Mediterranean Cooperation. More info: www.iucn-medmis.org Pag. 4/5 Mediterranean invasive species factsheet www.iucn-medmis.org MPAs, Country Date Density Measure Mljet, Croatia Before 2013 -- -- Isole Pelagie, Italy Before 2013 -- -- Zakynthos, Greece Before 2013 -- -- Kas-Kekova, Turkey Before 2013 -- -- Mljet, Croatia 21/11/2014 -- -- -- 15/06/2015 -- -- -- 15/06/2016 -- -- -- 15/06/2016 -- -- -- 15/06/2016 -- -- -- 20/06/2016 -- -- -- 25/07/2016 -- -- -- 18/08/2016 -- -- How to cite this tab: Aplysia dactylomela - Invasive Alien Species Fact Sheet for Mediterranean Network of MPAs. From Online Database MedMIS (IUCN Center for Mediterranean Cooperation, Download date 05/10/2021. More information about this species from: Otero, M., Cebrian, E., Francour, P., Galil, B., Savini, D. 2013. Monitoring Marine Invasive Species in Mediterranean Marine Protected Areas (MPAs): A strategy and practical guide for managers. Malaga, Spain: IUCN. 136 pages www.iucn.org/dbtw-wpd/edocs/2013-008-Es.pdf . 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