The butterfly blenny (''Blennius ocellaris'') is a small marine blenniid

fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

of Northern and

Western Europe Western Europe is the western region of Europe. The region's extent varies depending on context. The concept of "the West" appeared in Europe in juxtaposition to "the East" and originally applied to the Western half of the ancient Mediterranean ...

, as well as the

Mediterranean Sea The Mediterranean Sea ( ) is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean basin and almost completely enclosed by land: on the east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern Eur ...

and

Black Sea The Black Sea is a marginal sea, marginal Mediterranean sea (oceanography), mediterranean sea lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bound ...

and

Morocco Morocco, officially the Kingdom of Morocco, is a country in the Maghreb region of North Africa. It has coastlines on the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to Algeria–Morocc ...

. It is usually found at a depth of down, especially in areas with a rocky floor.

Description

The butterfly blenny has a deep body at the front, tapering rather quickly to the caudal peduncle. It can grow as large as in length. It has 11 to 12 dorsal spines, 14 to 16 dorsal soft rays, 2 anal spines and 15 to 16 anal soft rays. It has tentacles on the nasal opening, above the eye and on the nape near the first dorsal fin ray. The

lateral line The lateral line, also called the lateral line organ (LLO), is a system of sensory organs found in fish, used to detect movement, vibration, and pressure gradients in the surrounding water. The sensory ability is achieved via modified epithelia ...

is discontinuous. The front part of the

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

is much higher than the remainder of the fin, and the anal fin is also long, running half the body length. The pelvic fins are set well forward and are divided in two. This fish is a mottled brownish-grey, with five to seven dark vertical bars. There is a large bluish-black eyespot surrounded by a white ring on the 6th and 7th rays of the dorsal fin.

Distribution and habitat

The butterfly blenny has a range that extends from the Mediterranean Sea, up the cost of Spain, Portugal and France to the

English Channel The English Channel, also known as the Channel, is an arm of the Atlantic Ocean that separates Southern England from northern France. It links to the southern part of the North Sea by the Strait of Dover at its northeastern end. It is the busi ...

and the

Irish Sea The Irish Sea is a body of water that separates the islands of Ireland and Great Britain. It is linked to the Celtic Sea in the south by St George's Channel and to the Inner Seas off the West Coast of Scotland in the north by the North Ch ...

. It is found over rocky substrates covered with seaweed and this means that it is seldom caught in trawls, and may be more common than it seems. It occurs in the subtidal zone, and its depth range is down to about .

Reproduction

It spawns in late spring (as late as June in the

) and hides the eggs under an abandoned shell; the male guards the eggs. An individual near

Plymouth Plymouth ( ) is a port city status in the United Kingdom, city and unitary authority in Devon, South West England. It is located on Devon's south coast between the rivers River Plym, Plym and River Tamar, Tamar, about southwest of Exeter and ...

was found to be nesting inside the cavity of a large thigh bone.

References

{{Taxonbar, from=Q1474934 Butterfly blenny Fish described in 1758 Taxa named by Carl Linnaeus