Auxis
Auxis | ||||||||||||
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Loggerhead bonito ( auxis thazard ) |
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Systematics | ||||||||||||
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Scientific name | ||||||||||||
Auxis | ||||||||||||
Cuvier , 1829 |
Auxis is a species of fish in the family of mackerel and tuna (Scombridae) with few species. It isclosely relatedto the species of tuna ( Thunnus ) and occurs worldwide in tropical and subtropical seas, including the Mediterranean and the Black Sea .
features
The Auxis species are 50 to 65 cm long and have a strong, spindle-shaped body with a pointed head and a terminal mouth. The teeth are small, conical and lined up in each jaw. Except for a scaly corset on the front body, the fish are scaly. The two dorsal fins are separated by a wide gap that is as long as the base of the first dorsal fin. This is supported by 10 to 12 fin spines. There are 8 rafts between the second dorsal fin and the caudal fin, and 7 rafts between the anal fin and caudal fin. The pectoral fins are short. There is a strong, bony side keel on each side of the tail stalk, followed by two smaller kills. A swim bladder is missing. The number of vertebrae is 39.
Auxis species have a dark, black-blue back, the top of the head is deep purple or almost black. The belly is whitish and without stripes or dots. The pectoral and pelvic fins are purple on the outside and black on the inside.
Way of life
Auxis are real schooling fish and live epipelagically in the open ocean. Their diet is largely determined by the size of their gill rakes and consists of small fish, squids and pelagic crustaceans . Auxis species themselves are hunted by large tunas, swordfish-like fish , barracudas and sharks. In many parts of their range, they probably multiply throughout the year, in others only at certain times of the year. A female can shed up to a million eggs in one act of spawning.
species
There are four types:
- Auxis brachydorax Collette & Aadland , 1996
- Auxis eudorax Collette & Aadland , 1996
- Auxis rochei ( Risso , 1810)
- Loggerhead bonito ( Auxis thazard ( Lacepède , 1800) )
fishing
Like all tuna relatives, auxis species are fished commercially.
literature
- Bruce B. Collette, Cornelia E. Nauen: Scombrids of the world. An annotated and illustrated catalog of tunas, mackerels, bonitos and related species known to date (= FAO Species Catalog. Vol. 2 = FAO Fisheries Synopsis. No. 125, Vol. 2). United Nations Development Program et al., Rome 1983, ISBN 92-5-101381-0 .
Web links
- Auxis on Fishbase.org (English)