Atlantic lizardfish
| Atlantic lizardfish | ||||||||||||
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Atlantic lizardfish ( Synodus saurus ) photographed in Italian waters. Image by Rossella Baldacconi |
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| Scientific name | ||||||||||||
| Synodus saurus | ||||||||||||
| ( Linnaeus , 1758) |
The Atlantic lizardfish ( Synodus saurus ) is a predatory fish from the lizardfish family ( Synodontidae ). It is well camouflaged and lies in wait for its prey on the ocean floor. The head and body of this fish are reminiscent of a lizard . The species was first described in 1758 by Carl von Linné .
features
The Atlantic lizardfish is about 20 cm long on average and reaches maximum lengths of around 40 cm.
You can recognize it among other things by its large mouth, which is covered with many pointed teeth . The gap in the mouth extends far behind the eye . The fish appears brownish to sand-colored overall, with the underside being paler. Atlantic lizardfish have about 8 more or less dark transverse bands on their back. These are located between the back of the head and the base of the caudal fin (caudalis). Larger specimens are patterned with fine, irregular lines and dots. The Atlantic lizardfish has irregular blue or white lines on its flanks. In contrast to Synodus synodus there is no dark point on the tip of the snout.
The pattern of the Atlantic lizardfish varies depending on the subsurface to ensure optimal camouflage. For example, the transverse ligaments on the back on rocky ground are wider and appear brownish.
The head is relatively short and only takes up about 1/4 - 2/9 of the body length without the caudal fin . The head is uneven on the top. The width of the skull bone between the eyes (interorbital width ) varies between 1/5 - 2/3 the length of the head. In the Atlantic lizardfish, the eye is rather medium-sized with a diameter of 1/8 - 3/16 of the head length. The length of the snout corresponds approximately to the diameter of the eye or is a little larger than this. The base of the anal fin (analis) is short. It is about as long as the base of the dorsal fin (dorsalis) or slightly shorter. The pectoral fins (pectoralia) are short and extend to the base of the pelvic fins (ventralia), but not to the base of the dorsal fin . 11–13 fin rays support the dorsal fin , the anal fin is supported by 9–12 fin rays. The pelvic fins each have 8 fin rays and the pectoral fins each have 12-14 fin rays. There is also a small adipose fin (adipose). The body of the Atlantic lizardfish is scaled. It has 54-60 scales along the sidelines . There are 3½ scales between the sideline and the center of the base of the dorsal fin .
The sex can only be determined on the basis of the gonads ( gonads ), so Synodus saurus has no external sexual dimorphism .
distribution and habitat
The Atlantic lizardfish is found in the Eastern Atlantic from Morocco to Cape Verde , in the Azores and in the Mediterranean . Its distribution area in the West Atlantic includes Bermuda , the Bahamas and the Lesser Antilles (Leeward Islands).
The Atlantic lizardfish are preferred to be found on sandy or sandy-rocky ground near islands. It is also often found near seagrass meadows . It usually stays at depths of 20 m or less. However, these fish have also been detected at depths of up to 400 m.
behavior
The Atlantic lizardfish are usually found lurking on the seabed. One often sees him with his front half raised and his head turned up. He is supported by his pelvic fins . If the bottom is sandy, it happens that these fish bury themselves.
Usually, Atlantic lizardfish swim no more than half a meter from the bottom. However, this does not apply to hunting. Here, they often observe and pursue potential prey fish for a long time before they dare to attack. At a suitable place, the lizardfish lurks motionless and well camouflaged on the bottom. When he has decided on a prey fish, he starts a lightning-fast attack. It rises up to 5 m from the ground. In most cases, it then swims back directly to its previous location. Most attacks, however, are unsuccessful.
When in danger, the Atlantic lizardfish tries to intimidate the attacker with threatening gestures. It uses its large mouth, body and fins. If this does not work, he takes flight.
Atlantic lizardfish compete with each other for territory and good hunting grounds. They swim quickly towards each other with their dorsal fin raised to drive away competitors.
nutrition
The Atlantic lizardfish is an opportunistic predatory fish that feeds mainly on other fish. The fish that are most frequently available regionally and seasonally are hunted. He mainly focuses on juveniles of free-swimming schooling fish, such as sea bream (Sparidae) and herring (Clupeidae). Younger lizardfish choose smaller prey fish than their larger conspecifics. Invertebrates play a subordinate role as prey.
It has been demonstrated that Atlantic lizard fish also Anilocra physodes eat, a parasitic isopod . This opens up a new source of food for themselves and at the same time rid themselves of this parasite .
Reproduction
Little is known about the reproduction of Synodus saurus . Female Atlantic lizardfish reach sexual maturity after 3 years, the males after 2 years. The fish reproduce between June and October. The Spawning takes place at regular intervals. In between there are phases of rest in which the gonads (gonads) renew themselves . The eggs themselves are small and numerous. A single female lays between 2,000 and 100,000 eggs per spawning run, depending on body size.
It is believed that in June the males compete for females. In August it was also observed that some lizardfish reside in pairs. They are close together on the seabed, with the head of one fish on the tail fin of the other fish. Due to the lack of external sexual dimorphism , however, it cannot be determined whether these are males and females.
Atlantic lizardfish and human
Despite their gnarled mouth, Atlantic lizardfish are harmless to humans.
Synodus saurus does not play a major role economically. Professional fishermen only land it every now and then as bycatch . The species is listed as "Gamefish", so it is relevant in sport fishing .
On February 4th, 2009 the World Conservation Union (IUCN) rated the Atlantic lizardfish as "Least Concern" (LC = Least Concern). The population trend of the species is unknown, but Synodus saurus is a relatively common species in its respective range . In some places it is even assumed that the distribution area will increase. A threat to the stock from the low fishing pressure seems unlikely.
Web links
Individual evidence
- ↑ a b c d e f g Froese, R .; Pauly, D .; eds .: Species summary for Synodus saurus, Atlantic lizardfish. Retrieved November 16, 2019 .
- ↑ a b c d Whitehead, PJP; Bauchot, M.-L .; Hureau, J.-C .; Nielsen, J .; Tortonese, E. 1984 ed .: Fishes of the North-eastern Atlantic and the Mediterranean, Vol. 1 . Unesco, Bungay (United Kingdom) 1984, ISBN 92-3002215-2 .
- ↑ a b c Louisy, P .; Louisy, S .; Robin, J .: Europe and mediterranean marine fish identification guide - Fully updated and enriched edition . Ulmer, Paris 2015.
- ↑ a b c d e f Soares, MSC; Barreiros, JP; Sousa L. & Santos, RS: Agonistic and predatory behavior of the lizardfish Synodus saurus (Linnaeus, 1758) (Actinopterygii: Synodontidae) from the Azores . 2002.
- ↑ a b c Sousa, L .; Barreiros, JP; Soares, MSC; Hostim-Silva, M .; Santos, RS: Preliminary notes on the reproductive biology of the lizardfish, Synodus saurus (Actynopterygii: Synodontidae) in the Azores . 2003.
- ↑ a b c d Edwards, A .; Russell, B .: Synodus saurus. The IUCN Red List of Threatened Species . 2010.
- ↑ Esposito, V .; Battaglia, P .; Castriota, L .; Grazia Finoia, M .; Scotti, G .; Andaloro, F .: Diet of Atlantic lizardfish, Synodus saurus (Linnaeus, 1758) (Pisces: Synodontidae) in the central Mediterranean Sea . 2009.
- ↑ Barreiros, JP; Sousa, L .; Soares, MSC: Feeding habits of the lizardfish Synodus saurus (Linnaeus, 1758) (Actinopterygii: Synodontidae), from the Azores . 2003.
- ↑ Narvaez, P .; Barreiros, JP; Soares, MC: The parasitic isopod Anilocra physodes, as a novel food source for the lizardfish Synodus saurus (Synodontidae) . 2015.
- ↑ El Koutbia, M .; Ktari, MH; Ben Salem, M .: Stratégie de la reproduction chez Synodus saurus (Linné 1758), (Poissons Téléostéen), des côtes tunisiennes. ; The reproduction strategy of Synodus saurus (Linne, 1758), (Fish, Teleostei), of the Tunisian Coasts . 1997.