Oilfish

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Oilfish
Fish4424 - Flickr - NOAA Photo Library.jpg

Oilfish ( Ruvettus pretiosus )

Systematics
Spinefish (Acanthopterygii)
Perch relatives (Percomorphaceae)
Order : Scombriformes
Family : Mackerel (Gempylidae)
Genre : Oilfish
Type : Oilfish
Scientific name of the  genus
Ruvettus
Cocco , 1833
Scientific name of the  species
Ruvettus pretiosus
Cocco, 1833

The oilfish ( Ruvettus pretiosus , Syn .: Ruvettus tydemani Weber, 1913 ) is a species of fish from the family of the mackerel and the only species of the genus Ruvettus . The oilfish inhabits seas of the tropical and temperate zones at a depth of 100 to 800 m alone or in pairs. Fish and cephalopods are the basis of the Ruvettus diet .

features

Adult specimens can reach lengths of 80 cm to over two meters and a weight of up to 63.5 kg. The species is similar to the related species Rexea solandri (King's Escolar), but has smaller eyes, a smaller mouth, and a lower dorsal fin. The color of the fish is a dark, reddish brown on the back and a paler, silvery hue on the belly. The eyes of the oilfish are " phosphorescent ". (This statement has caused a lot of controversy. On the one hand, it can only be about bioluminescence . On the other hand, "glowing eyes" would be a sensory-physiological problem. Either one meant eyes with reflective tapetum lucidum as in cats and other nocturnal animals, too B. Deep-sea) fish. Or one observed a glow not in the living, but in the decaying fish colonized by luminescent bacteria. Or there is a luminescent organ around the eye or on the iris - to illuminate the immediate surroundings, as it is similar to Anomalopidae is known.)

Young fish

The scales, which appear quite late in development, are complex and give the fish a rough surface that noticeably reduces the frictional resistance when swimming. The anterior dorsal fin is supported by 14–16 hard rays; it becomes relatively lower as the size of the fish increases. The pelvic fins are small but always distinct.

Ruvettus pretiosus (scales only drawn in one place)

use

The meat of the fish oil is indeed edible, but the meat contained in the 18 to 21% by weight oils , especially wax Sester , can stomach - intestinal discomfort such as diarrhea and vomiting , and cramps and headaches cause. In Japan and Italy there is an import ban on the meat of the oil fish. In Australia , the sale of meat as food is prohibited. The German Federal Institute for Risk Assessment also advises caution when consuming the fish, which, like the related Escolar , is occasionally sold under the trade names butter mackerel or butterfish (which favors confusion with the only very distantly related butterfish ).

Ruvettus pretiosus - young fish (approx. 20 cm long); still scaly; Flössel not yet differentiated

In Polynesia , the oilfish known under the Polynesian name palu is caught at night with lines at a distance of up to 400 meters from the reefs .

In 2006, the Hong Kong- based supermarket chain PARKnSHOP sold canned meats from oil fish under the English name "cod fish (oilfish)". Since Cod is the English word for cod , many customers thought the canned food was for those with cod and then suffered diarrhea. The company denied responsibility for fourteen complaints, claiming the fish was intended for human consumption. Similar incidents were reported from Chinese supermarkets in Canada in early 2007.

During expeditions in search of the coelacanth in the 1950s, fishermen from the Comoros tried again and again to sell oilfish they had caught as alleged coelaceans to researcher JLB Smith .

Web links

Commons : Ruvettus pretiosus  - collection of images, videos and audio files

Individual evidence

  1. ^ Robin Hooper: Denizens of the Deep: The Semantic History of Proto-Polynesian * palu. In: Andrew Pawley (Ed.): Man and a Half. Essays in Pacific Anthropology and Ethnobiology in Honor of Ralph Bulmer. The Polynesian Society, Aukland 1991, pp. 119-127, here p. 121