''Solea senegalensis'', the Senegalese sole, is a species of

flatfish A flatfish is a member of the Ray-finned fish, ray-finned demersal fish order (biology), order Pleuronectiformes, also called the Heterosomata, sometimes classified as a suborder of Perciformes. In many species, both eyes lie on one side of the ...

from the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

of the true soles, the

Soleidae The true soles are a family, Soleidae, of flatfishes. It includes saltwater and brackish water species in the East Atlantic, Indian Ocean, and West and Central Pacific Ocean. Freshwater species are found in Africa, southern Asia, New Guinea, an ...

, from the eastern Atlantic and the Mediterranean Sea.

Description

''Solea senegalensis'' is very similar to the

common sole The common sole, Dover sole, or black sole (''Solea solea'') is a species of flatfish in the family Soleidae. It is one of the largest fish in the ''Solea'' genus. It lives on the sandy or muddy seabed of the northern Atlantic and the Mediterra ...

and like it, it has a flattened, oval body with the

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through conv ...

starting on the upper profile of the head to the front of the upper eye. The dorsal fin has 73–86 rays, the

anal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

has 61–74 rays and there is a well developed

pectoral fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as ...

on each side of its body which has 7–10 rays. There are numerous, small, hair like fringes on the blind side of the head and the distance between the upper eye and the dorsal profile of the head is obviously greater than the diameter of the eye. The anterior nostril on the blind-side is surrounded by a small ridge but it is not enlarged. The

caudal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

is attached to the last rays of the dorsal and anal fins by a narrow membrane. 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 epithelial ...

is made up of 120–138 pored scales. It is greyish brown in colour on the eyed side marked with numerous blue spots, the spots tend to disappear in dead specimens. The pectoral fin on the eyed side has a nearly black membrane contrasting with cream coloured fin rays while the caudal fin is plain. The blind side is whitish. The main identifying feature which separates this species from the common sole is the black colour of the membrane between the rays on the pectoral fin on its eyed-side whereas the common sole has a neat black spot close to the margin of the eyed side pectoral fin. It grows to a

standard length Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish m ...

of 60 cm but is more usually 45 cm.

Distribution

''Solea senegalensis'' occurs in the eastern Atlantic from southern Great Britain and Ireland, where it is rare, to Angola, including the

Canary Islands The Canary Islands (; es, Canarias, ), also known informally as the Canaries, are a Spanish autonomous community and archipelago in the Atlantic Ocean, in Macaronesia. At their closest point to the African mainland, they are west of Morocc ...

. It entered the Mediterranean Sea via Gibraltar in the early 20th century, fast expanded in the western Basin as far east as northern Tunisia where it is an important resource and is now found in the Aegean Sea till the Sea of Marmara.Atlas of Exotic Fishes in the Mediterranean Sea (Solea senegalensis). 2nd Edition. 2021. 366p. CIESM Publishers, Paris, Monaco.https://ciesm.org/atlas/fishes_2nd_edition/Solea_senegalensis.pdf

Habitat and biology

''Solea senegalensis'' is a

demersal The demersal zone is the part of the sea or ocean (or deep lake) consisting of the part of the water column near to (and significantly affected by) the seabed and the benthos. The demersal zone is just above the benthic zone and forms a layer of ...

marine

which occurs on sandy or muddy bottoms, these can be in varied habitats from brackish lagoons and shallow waters to coastal regions where the water can be 100 m in depth. The adults feed mainly on small benthic invertebrates, especially

polychaete Polychaeta () is a paraphyletic class (biology), class of generally marine invertebrate, marine annelid worms, common name, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that ...

s and

bivalve Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...

s, with some small crustaceans. Females attain sexual maturity at around 3 years of age and a total length of 32 cm. Spawning takes place during the summer peaking in June around the

Iberian Peninsula The Iberian Peninsula (), ** * Aragonese and Occitan: ''Peninsula Iberica'' ** ** * french: Péninsule Ibérique * mwl, Península Eibérica * eu, Iberiar penintsula also known as Iberia, is a peninsula in southwestern Europe, defi ...

and in the

Bay of Biscay The Bay of Biscay (), known in Spain as the Gulf of Biscay ( es, Golfo de Vizcaya, eu, Bizkaiko Golkoa), and in France and some border regions as the Gulf of Gascony (french: Golfe de Gascogne, oc, Golf de Gasconha, br, Pleg-mor Gwaskogn), ...

when the water temperature is between 15 °C and 20 °C.

Taxonomy

Over much of its range ''S. senegalensis'' is

sympatric In biology, two related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter one another. An initially interbreeding population that splits into two or more distinct species sh ...

with the rather similar common sole and has been considered a

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

by some authors in the past, ''Solea vulgaris melanochira''. It is however more closely related to the east Mediterranean Egyptian sole (''

Solea aegyptiaca The Egyptian sole (''Solea aegyptiaca'') is a species of flatfish in the true sole family, Soleidae. It lives on the sandy or muddy seabed of the Mediterranean Sea, and is now colonising the Red Sea. It often semi-immerses itself in the substra ...

'') than it is to the common sole, and where these two species' ranges meet there is a

hybrid zone A hybrid zone exists where the ranges of two interbreeding species or diverged intraspecific lineages meet and cross-fertilize. Hybrid zones can form ''in situ'' due to the evolution of a new lineage but generally they result from secondary contact ...

, with hybrids being detected from the

Gulf of Lions The Gulf of Lion or Gulf of Lions (French: ''golfe du Lion'', Spanish: ''golfo de León'', Italian: ''Golfo del Leone'', Occitan: ''golf del/dau Leon'', Catalan: ''golf del Lleó'', Medieval Latin: ''sinus Leonis'', ''mare Leonis'', Classical L ...

and the coats of Tunisia as demonstrated in the research of Dr. Khaled Ouanes. ''S. senegalensis'' is thought to have invaded the Mediterranean from the eastern Atlantic through the

Straits of Gibraltar The Strait of Gibraltar ( ar, مضيق جبل طارق, Maḍīq Jabal Ṭāriq; es, Estrecho de Gibraltar, Archaic: Pillars of Hercules), also known as the Straits of Gibraltar, is a narrow strait that connects the Atlantic Ocean to the Medit ...

, a phenomenon knows as Herculean migration after the

Pillars of Hercules The Pillars of Hercules ( la, Columnae Herculis, grc, Ἡράκλειαι Στῆλαι, , ar, أعمدة هرقل, Aʿmidat Hiraql, es, Columnas de Hércules) was the phrase that was applied in Antiquity to the promontories that flank t ...

Human interaction

In Europe both the common sole and the Senegalese sole are landed and marketed and there is little distinction made between them in statistics. There are, however, different geographical preferences with the common sole being preferred in northern Europe and the Senegalese sole being preferred in more southerly areas and these preferences are reflected in the higher market price for common sole in northern and western Europe while Senegalese sole is more valuable in southern Europe. Off Mauritania there is an artisanal fishery for this species and the artisanal catch between 2006 and 2010 fluctuated between 117,328 kg to as low as 9,049 kg but information on fishing effort is lacking. It is widely produced in extensive aquaculture in Portugal and Spain. Abstract The flesh is sold fresh, normally as fillets with smaller fillets going to domestic consumers and larger fillets to commercial markets such as hotels and restaurants.

References

{{Taxonbar, from=Q849278 Soleidae Fish of the Atlantic Ocean Fish of the Mediterranean Sea Fish described in 1858 Taxa named by Johann Jakob Kaup