Chelidonichthys cuculus

Chelidonichthys cuculus

The red gurnard (Chelidonichthys cuculus) is a sea fish belonging to the Triglidae family.

Systematic –
From a systematic point of view it belongs to:
Eukaryota domain,
Kingdom Animalia,
Subkingdom Eumetazoa,
Phylum Chordata,
Subphylum Vertebrata,
Superclass Gnathostomata,
Class Actinopterygii,
Infraclass Teleostei,
Order Scorpaeniformes,
Suborder Scorpaenoidea,
Triglidae family,
Genus Chelidonichthys,
Species C. cuculus.
The term is basionym:
– Trigla cuculus Linnaeus, 1758.
The terms are synonymous:
– Aspitrigla cuculus (Linnaeus, 1758);
– Chelidonichthys cululus (Linnaeus, 1758);
– Cheliodonichthys cuculus (Linnaeus, 1758);
– Trigla grunniens Lacepède, 1801;
– Trigla pini Bloch, 1793.

Geographic Distribution and Habitat –
Chelidonichthys cuculus is a fish found in various seas, including: Eastern Atlantic Ocean, from southern Scotland, although it has rarely been reported from Norway, as far south as Mauritania, including Madeira, the Azores and the Canary Islands. It is found throughout the Mediterranean Sea and in the Black Sea. It is frequent on the Italian coasts, especially in the Adriatic.
Regarding its habitat, it is a demersal species that has been observed at depths between 15 and 400 m, although the usual range is between 30 and 250 m. It is typically recorded in habitats dominated by sand or gravel, although it has also been found in rocky and muddy habitats where it generally lives on seabeds up to 300 meters deep and in summer it comes very close to the shore.

Description –
The Chelidonichthys cuculus is a fish with a color that is always reddish or orange. The color is lighter on the sides and whitish on the belly. The dorsal fins are reddish carmine. The caudal, reddish, is bordered in black at the back. The pectorals are pale pink with dark streaks. The anal is creamy white and the ventrals pink.
This fish has a total length that can reach 50 cm in length, but on average it is 25-30 cm, although a maximum length of 70 cm has been published.
The body is slender and tapers towards the caudal peduncle, which is thin. It is slightly compressed laterally and is covered with small scales, missing in the lower part.
The scales of the lateral line are very developed vertically and transformed into bony shields without crests and spines (65-70).
The head is robust and armored with spiny bony plates, it has a concave snout profile and the pre-opercular bone just extended into a serrated rostrum, on the sides of which there are 5 to 7 denticles in juveniles. The anterior nasal opening is a small hole, the posterior one is formed by a thin vertical slit.
The eye is circular, relatively large and slightly protruding from the profile of the head. Two upwardly directed spines are located on the superoanterior margin of the orbit. The spines of the opercular pieces and the coracoid spine are evident. All the bony plates covering the head are grainy and striated, with the free margins spiny or serrated.
The mouth, almost horizontal, opens downwards. The teeth are small and irregularly arranged in five rows in the upper jaw and four in the lower jaw.
It has two dorsal fins that are housed in a dorsal groove, at the edges of which there is a series of 26-28 spiny plates. The first fin has 8-10 spiny rays, of which the 2nd is the longest, and is triangular in shape. The second fin has 17-18 soft rays and arises immediately after the first. The anal fin has 16-18 soft rays and is opposite and similar to the second dorsal. The caudal fin has the posterior margin clearly hollowed in the center and the lobes are pointed. The pectorals extend up to approximately the height of the third anal ray and have 13-14 rays, of which the last 3 are free, rather thick and elongated. The ventral ones (1 spiny ray and 5 soft ones) are a little shorter than the pectoral ones and reach up to the anal opening.

Biology –
The Chelidonichthys cuculus is a fish with a reproduction period which probably goes from April to June. The female is known to lay eggs in summer. Sexual maturity is reached at approximately 26.6 cm and the maximum reported age is 21 years.

Ecological Role –
Chelidonichthys cuculus was first formally described in 1758 as Trigla cuculus by Carl Linnaeus in the tenth edition of his Systema Naturae with the type locality indicated as the Mediterranean Sea. In 1925 the American zoologist Henry Weed Fowler classified this species in the monotypic taxon Aspitrigla, a subgenus of Chelidonichthys, and type species of the subgenus. The specific name cuculus comes from the Latin “cuckoo”, a name that can be traced back to Aristotle, who claimed that these fish made cuckoo-like sounds when taken from the water.
It is a species that feeds on crustaceans and fish or other animals.
In a study conducted on this species in the Adriatic Sea it was found to feed almost entirely (more than 90%) on malacostracan crustaceans with fish, molluscs and echinoderms taken in much smaller quantities. Prey is detected using the enlarged and separated rays of the pectoral fins. This species produces sounds, similar to a frog.
This fish is caught with trawl nets and rarely bites the hooks. It is not commercially exploited in its Atlantic range, although it can be caught and eaten as bycatch. However, its meats are highly appreciated for preparing soups.
In England it is fished off the coast of Cornwall and is of increasing although still less economic interest. In the Mediterranean it is of minor commercial interest. These fish are regularly present in the fish markets of Spain, Morocco, Italy, Cyprus and Egypt, and sometimes in France, England, Greece, Ireland and Turkey, although they are rarely traded in Tunisia. The catch is sold fresh, chilled and frozen.

Guido Bissanti

Sources
– Wikipedia, the free encyclopedia.
– GBIF, the Global Biodiversity Information Facility.
– Louisy P., 2016. Guide to the identification of marine fishes of Europe and the Mediterranean. Il Castello Editore, Milan.
– Nikiforos G., 2008. Fauna of the Mediterranean. Giunti Editore, Florence.

Photo source:
– https://www.athos-scuba.gr/gallery/marinelife/fishes?i=Chelidonichthys-cuculus
– https://upload.wikimedia.org/wikipedia/commons/3/37/FMIB_51240_Redgurnard_%28Trigla_cuculus%29.jpeg