Mediterranean marlin

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Mediterranean marlin
Mediterranean marlin in Buffon's Histoire naturelle (1828–49).

Mediterranean marlin in Buffon's Histoire naturelle (1828–49).

Systematics
Carangaria
Order : Carangiformes
Superfamily : Swordfish relatives (Xiphioidea)
Family : Spearfish (Istiophoridae)
Genre : Tetrapturus
Type : Mediterranean marlin
Scientific name
Tetrapturus belone
Rafinesque , 1810

The Mediterranean marlin ( Tetrapturus belone ) is a large predatory fish that is endemic to the Mediterranean , where it is the most common marlin . It is absent in the Black and Azov Seas , east of the Ionian Sea there are no adult animals, only larvae and juvenile fish.

features

The Mediterranean marlin grows to a maximum of eight feet, but usually stays two feet in length. The maximum published weight is 70 kg and the average weight is 10 to 30 kg. The body is elongated, laterally flattened and densely covered with elongated scales, which each end in three to five points at their rear edge. The single sideline is clearly visible. The number of vertebrae is 24, 12 trunk and 12 tail vertebrae. The fish are dark blue to almost black on the back and silvery white on the belly. There are usually no spots or other patterns on the body or fins.

The long first dorsal fin extends from the rear edge of the gill cover to just before the second dorsal fin and is supported by 39 to 46 fin rays, the second by 5 to 7. The first dorsal fin has a high, rounded tip at the front that is higher than the body height of the fish is. It then drops steeply up to the 10th fin ray, but then remains at the same height. The second dorsal fin has 5 to 7 fin rays. Of the two anal fins, the first has 11 to 15 scaly fin rays, the second 6 to 7 fin rays. The second dorsal and anal fins are symmetrically opposite each other and are very similar in shape and size. The short pectoral fins are supported by 16 to 20 fin rays and reach 10 to 13% of the body length. Its upper edge is curved, the lower one straight, the end pointed. The pelvic fins are slender, long, slightly shorter than twice the length of the pectoral fin, and can be laid in pits. The tail fin stalk is strongly flattened on the sides and provided with a double keel and a shallow notch on the back and the belly side on each side. The anus sits well in front of the beginning of the first anal fin.

Its spear-like, elongated rostrum with a round cross-section is significantly shorter than that of other spearfish and reaches a maximum of 18% of the body length. Both jaws and the palatine bone are covered with fine teeth, gill traps are missing, the right and left Branchiostegal membranes have grown together completely, but are free of the isthmus .

Way of life

The Mediterranean spearfish is an oceanic, pelagic fish that does not normally approach the coast and resides above the thermocline between warmer surface and cold deep waters. As reported by other spearfishes , the Mediterranean marlins are said to be often found in pairs. This may have something to do with his hunting behavior. Tetrapturus belone is a predatory fish that feeds on fish, cephalopods, and crustaceans. The prey fish include sardines , mackerel , flying fish , garfish , jackfish and golden mackerel . The breeding season is likely to be winter or spring. The pelagic eggs are approximately 1.48 mm in diameter and contain a yellowish-green drop of fat.

use

The Mediterranean marlin is caught with harpoons, longlines, drift nets and gill nets. It is mainly a bycatch when fishing for swordfish and for red and albacore tuna .

literature

  • Izumi Nakamura: FAO Species Catalog An Annotated and Illustrated Catalog of Marlins, Sailfishes, Spearfishes and Swordfishes Known to date. Rome 1985, ISBN 92-5-102232-1 . (on-line)

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