Chelidonichthys lucerna

Chelidonichthys lucerna

The gurnard or sapphirine gurnard, tube-fish, tubfish, yellow gurnard (Chelidonichthys lucerna Linnaeus, 1758) is a 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. lucerna.
The term is basionym:
– Trigla lucerna Linnaeus, 1758.
The terms are synonymous:
– Chlidonichthys lucernus (Linnaeus, 1758);
– Trigla corax Bonaparte, 1834;
– Trigla corvus Rafinesque, 1810;
– Trigla hirundo Linnaeus, 1758;
– Trigla microlepidota Risso, 1824.

Geographic Distribution and Habitat –
Chelidonichthys lucerna is a teleost fish that lives in the eastern Atlantic Ocean, where it is found from Norway south along the European and African coasts to Ghana. It is present throughout the Mediterranean Sea and also in the Black Sea. It is absent in Madeira and the Azores, but is found around the Canary Islands.
In Italy it is frequent on the coasts, especially in the Adriatic and in the Venetian lagoon.
Its marine habitat is that of sandy, mud-sand or gravel bottoms at depths between 20 and 300 m. During the summer it may spend more time closer to the surface in water as shallow as 10 m and juveniles can be found in brackish water in lagoons, estuaries and even the lower reaches of rivers. Walk on the bottom with the free spokes of the pectorals.

Description –
The Chelidonichthys lucerna is a fish that has a large and massive head with a clearly visible and protruding snout, the spine on the operculum is not very large. The operculum is equipped with several pointed appendages.
The color of the body is brownish or reddish on the back while on the sides it turns salmon pink. The belly is white. It reaches 70 cm in length (but on average it is around 30 cm) and weighs 6 kg.
The profile of the forehead is straight, not sunken. The eye is circular and of modest size.
The body becomes thinner after the second half. The scales are small and are not present ventrally. Along the lateral line there are several protruding tubules.
The mouth is wide and lower, with bands of heart-shaped teeth on the jaws.
The two dorsal fins are inserted into a groove bordered by spiny plates, with a backward tip. The first has 8-9 spiny rays, of which the second is the longest, and is triangular in shape. The second is inserted immediately after the first; it has 15-18 soft, not very high rays and is extensive. The anal (14-16 soft rays) is opposite the second dorsal, but is a little shorter. The caudal (12 rays) has a slightly hollowed posterior edge in the centre.
The pectorals (13-14 rays) are very broad and fan-shaped; the last three rays are free, elongated and articulated. The ventral ones have 1 spiny and 5 soft rays and are large, but much smaller than the pectoral ones.
The pectoral fins are black-blue with bright electric blue patterns and a black spot at the base. The lateral line is clear, each scale on the lateral line has a backward-pointing denticle. The dorsal fin is pointed.
In the juvenile forms the color can take on different shades, from dirty red or yellowish to greyish with green or brown spots. Pink white belly and carminate red head. The unpaired fins are reddish with spots. The pectorals, in juvenile specimens, have a blue border and on the inside a blue-black spot with light blue eyespots; in adults the black spot becomes less dark and the dots disappear, while the blue border remains and the general color darkens towards greenish or purple.
This species makes sounds such as grunting or growling, using muscles associated with the swim bladder, it is thought that these sounds are used to keep schools together. It also emits a dull noise even out of the water.

Biology –
The Chelidonichthys lucerna is a fish with a reproduction period around December-February; it spawns between May and July in the northern parts of its range, while it spawns from November to February off the coast of Egypt.
The male and female form a distinct pair to lay eggs. The eggs are pelagic and in the larvae and post-larvae all the pectoral fin rays are contained within the fin membrane.
These fish begin to reach sexual maturity at a total length of 13 cm, and all fish over 20 cm in length are mature.

Ecological Role –
Chelidonichthys lucerna is an opportunistic predator that feeds on benthic prey, in particular crustaceans and smaller fish. The majority of their diet in a study conducted in the northwestern Mediterranean consisted of crustaceans, mainly Decapoda and especially crabs, with species such as Goneplax rhomboides and Liocarcinus spp. and caridean shrimp of the Philocheras genus, while among the fish caught the European anchovy (Engraulis encrasicolus) and the black goby (Gobius niger) predominated. Shellfish formed a more important part of the diet in the summer, while fish gained importance during the winter. They are also known to eat molluscs and polychaetes. Prey hidden in the substrate can be detected using sensory organs on the long, separated rays of the pectoral fins.
If disturbed, this fish becomes buried and when chased, it clouds the water to confuse the predator.
It is also targeted by commercial fishermen, but the quantity caught is relatively low, the average reported global landings over the period 2011 to 2015 was 4,429 tonnes. A large portion of these catches are made in the North Sea (52%) and the Eastern Channel (37%), however, actual landings are not broken down by species.
Together with Chelidonichthys cuculus and Eutrigla gurnardus, they have been recognized as potentially commercial species and this has led to recommendations made by ICES to monitor landings and discards and to obtain population biology data used to assess stocking. However, these data are missing for all three exploited species, particularly for C. lucerna.
Fishing is done with trawl nets, gill nets, longlines and lines.
The meat is white and tender, much appreciated. Not too large specimens are usually consumed, weighing between two ounces and half a kilo. It can be fried or baked, usually after being filleted. However, there are also various recipes for stewed cooking, accompanied by tomatoes or other vegetables.

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://inaturalist-open-data.s3.amazonaws.com/photos/279330602/original.jpeg