Aplysia fasciata

Aplysia fasciata  Poiret, 1789

Aplysia fasciata by Carlos Fernández-Cid




































Aplysia fasciata  Poiret, 1789

 Classification according to Bouchet et al. (2017)
Taxonomic source: World Register of Marine Species (AphiaID: 138755).

  • Aplysia brasiliana Rang, 1828
  • Aplysia gracilis Eales, 1960
  • Aplysia lobiancoi Mazzarelli, 1890
  • Aplysia marmorata de Blainville, 1823
  • Aplysia neapolitana Delle Chiaje, 1824
  • Aplysia radiata Crouch, 1826
  • Aplysia sicula Swainson, 1840
  • Aplysia vulgaris de Blainville, 1823
  • Aplysia willcoxi Heilprin, 1887
  • Aplysia winneba Eales, 1957
  • Laplysia alba Cuvier, 1803
  • Laplysia camelus Cuvier, 1803
  • Laplysia fasciata Poiret, 1789 (original)

This is one of the larger species of sea hares in the world, as it can measure more than 30cm in length and weight over 1.5 kg. The coloration is variable but, often, specimens have an homogeneous dark brown color, at times with white spots on the outer face of the parapodia, sides of the body and head. Larger size specimens can be almost black with light violet hue. The body texture is very soft when touched. Sometimes the margins of the parapodia, rhinophores and the underside of the foot are reddish. The rhinophores are short and auriculate. The parapodia are very broad and are completely free at the rear end, which allows individuals of this species make swimming motions. The foot is narrow, with the same color of the body, and the tail is short. The shell is internal and is wide, as it measures up to 50 mm in the largest specimens, and it is covered by the dorsal mantle epithelium. The foramen can be very small (2-3 mm diameter) or absent. In the reproductive the penis highlights, as it is long, thin and colored whitish.

This species, like others of the same kind in Europe, lives in shallow coastal waters from the intertidal zone to a depth of 15-20 m. This is a nocturnal species as it is at night when it is mostly active. Nutrition is herbivorous, as in other species of the order Anaspidea, and it is reported feeding on algal species of genus Ulva, Enteromorpha, Jania, Pterocladia and Laurencia. The broad parapodia, separated at the rear end, allows this species to swim for extended periods and it is not uncommon to see them swimming near beaches or inside ports. When they are abruptly disturbed, these animals secrete a whitish liquid from the opaline gland mixed with another purplish liquid secreted by the purple gland, both, apparently, with a defensive purpose. This species of Aplysia can also biosynthesize secondary metabolites of the group of aplykurodines, that accumulate in the outer parts of the animal, and are known to have toxic and repellent activity in laboratory conditions (Martínez, 1995). At the time of reproduction, usually at the end of summer or early autumn, many specimens are concentrated at shallow depth for intercourse, usually forming chains of several individuals. After mating the animals spawn, forming a ball of wrapped orange or yellowish cord which, if unwound can reach a length of 80 times the size of the animal and contain over 20 million eggs. Within the band, the eggs measure about 100 microns in diameter, and are located inside of capsules that may contain about 40 eggs on average (Thompson, 1976).


  • Aplysia. Derived from Greek word for “dirty”.
  • Fasciata. Means the animal parapodia are ornated with a color band.

This is a species that has a wide distribution. It has been cited for all European coasts both Atlantic and Mediterranean. It is also cited in the Atlantic coast of Africa (Morocco, Senegal, Angola, Ghana) and Cape Verde, Canary, Madeira and the Azores islands. It is an amphiatlantic species, as it has also been located in Costa Rica, Colombia, Cuba, Gulf of Mexico and St. Helens island, in the South Atlantic. In the Iberian Peninsula it is found in all coastal areas (Cervera et al., 2004). In Catalonia have been cited or observed in many localities of the Costa Brava, Maresme, Costa Dorada and in the southern coast of Tarragona.

Known georeferenced records of the species: Aplysia fasciata
: GROC 2010-2011
: Enric Madrenas
: João Pedro Silva
: Bernard Picton
: Manuel Ballesteros.
: M@re Nostrum
: Altres fonts
: Marine Regions


    Western Mediterranean:3 out of 5 stars
    Eastern Mediterranean:0 out of 5 stars
    Atlantic Ocean:0 out of 5 stars

This chart displays the monthly observation probability for Aplysia fasciata based on our own records.


Aplysia fasciata swimming. Filmed at L’Escala, Girona, on 10/11/2014 by Miquel Pontes
Video by Carles Galià


More pictures


Further reading

Cite this article as:

Ballesteros, Manuel, Enric Madrenas, Miquel Pontes (2012-2019) "Aplysia fasciata" in OPK-Opistobranquis, Published: 15/05/2012, Accessed: 16/06/2019 at (https://opistobranquis.info/en/Zu10D)

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