Jacks
| Jacks | ||||||||||||
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Caranx ignobilis |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Carangidae | ||||||||||||
| Rafinesque , 1815 |
The jacks (Carangidae) or horse mackerels are a family of perch relatives (Percomorpha). They live in tropical and subtropical zones of the Atlantic and Indo-Pacific and stay both in the open sea and near the coast on steeply sloping reefs.
features
Jacks can be very variable in shape. Their body can be spindle-shaped with a round cross-section, as in the genera Decapterus and Elagatis , or very high-backed and laterally flattened, as in Selene , or a shape between these two extremes. Most of them are silvery in color. Their maximum length is between 16 centimeters and 1.7 meters, depending on the species. The head often has a steep profile. The pectoral fins, caudal fins and the anterior area of the dorsal and anal fin are elongated and curved backwards. In some species, the continuous sideline is protected by prickly scales. Otherwise most species have only weak round scales , a few comb scales , and large parts of the body surface can also be bare. In larger juvenile fish and adult animals, the dorsal fin is divided, the first is supported by four to eight fin spines. These can also be very small and not connected by a fin membrane. The second dorsal fin has a fin spine and 17 to 44 soft rays. The anal fin usually has three fin spines and 15 to 39 soft rays. The first two of the fin spines, rarely only the first, are separated from the others. Up to nine small rafts can be found behind the dorsal and anal fin, as in tuna fish . The caudal peduncle is slender, the caudal fin forked.
In the fine mackerel ( Alectis ciliaris ), which occurs in all tropical seas and grows to a size of 60 centimeters, the first 7 to 8 rays of the dorsal fin and the first 4 to 5 rays of the anal fin are drawn out like a thread to double the body length.
Way of life
It is z. Some of them were fast-swimming predators in schools who developed convergent traits to mackerel and tuna . Although they are physoclist (have no connection between the swim bladder and the intestines), they can release gas from the swim bladder into the gill cavities for rapid pressure equalization . They are predatory fish that prey on fish larvae, small open water fish such as sardines and small pelagic crustaceans. Larger species, such as the thick-headed mackerel, also hunt waterfowl.
Systematics
The jackfish family was established in 1815 by the American polymath Constantine S. Rafinesque-Schmaltz . It is divided into four subfamilies ( Caranginae , Naucratinae , Scomberoidinae and Trachinotinae ), some authors also tribe , and about 150 species in 30 genera. The mackerel form a monophyletic clade with some other families , which is called the order Carangiformes in more recent systematics . However, they themselves are possibly not monophyletic in relation to the Cobia ( Rachycentron canadum ), the golden mackerel (Coryphaenidae) and the ship keeper (Echeneidae).
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use
Jackfish are popular table and frogfish and are of great economic importance. The horse mackerel ( Trachurus trachurus ), also known as horse mackerel, is an important product of the north-western European seas .
literature
- Joseph S. Nelson : Fishes of the World , John Wiley & Sons, 2006, ISBN 0-471-25031-7
- Kurt Fiedler: Textbook of Special Zoology, Volume II, Part 2: Fish , Gustav Fischer Verlag Jena, 1991, ISBN 3-334-00339-6
- Rudie H. Kuiter / Helmut Debelius : Atlas der Meeresfische , Kosmos-Verlag, 2006, ISBN 3-440-09562-2
- Hans A. Baensch / Robert Patzner: Mergus Sea Water Atlas Volume 7 Perciformes (perch-like) , Mergus-Verlag, Melle, ISBN 3-88244-107-0
Individual evidence
- ^ A b Santini, F. & Carnevale, G. (2014): First multilocus and densely sampled timetable of trevallies, pompanos and allies (Carangoidei, Percomorpha) suggests a Cretaceous origin and Eocene radiation of a major clade of piscivores. Molecular Phylogenetics and Evolution, November 2014, doi: 10.1016 / j.ympev.2014.10.018
- ↑ Richard C. Harrington, Brant C. Faircloth, Ron I. Eytan, W. Leo Smith, Thomas J. Near, Michael E. Alfaro & Matt Friedman: Phylogenomic analysis of carangimorph fishes reveals flatfish asymmetry arose in a blink of the evolutionary eye . BMC Evol Biol. 2016; 16: 224 Oct 2016. doi: 10.1186 / s12862-016-0786-x . PMC 5073739 (free full text).
Web links
- Jacks on Fishbase.org (English)