Oilfish (''Ruvettus pretiosus'') are a species of snake mackerel with a cosmopolitan distribution in

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

and

temperate In geography, the temperate climates of Earth occur in the middle latitudes (approximately 23.5° to 66.5° N/S of the Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ran ...

oceans. They can be found at depths from , but most often between . Oilfish can grow to a length of , though most do not exceed . It is the only known member of its

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

Description

Oilfish are large,

fusiform Fusiform (from Latin ''fusus'' ‘spindle’) means having a spindle (textiles), spindle-like shape that is wide in the middle and tapers at both ends. It is similar to the lemon (geometry), lemon-shape, but often implies a focal broadening of a ...

fish which often grow to and a maximum of . Other distinctive features of this fish include the large fangs, rough scales, two pairs of finlets, and a uniformly brown coloration. Oilfish meat is extremely oily, containing high lipid concentrations. Though edible, the oil mainly consists of

wax ester A wax ester (WE) is an ester of a fatty acid and a fatty alcohol. Wax esters are the main components of three commercially important waxes: carnauba wax, candelilla wax, and beeswax.. Wax esters are formed by combining one fatty acid with one ...

s, which makes the meat act as a

laxative Laxatives, purgatives, or aperients are substances that loosen stools and increase bowel movements. They are used to treat and prevent constipation. Laxatives vary as to how they work and the side effects they may have. Certain stimulant, lubri ...

if consumed in large quantities.

Habitat and ecology

Oilfish are distributed throughout tropical and temperate waters across the world, being recorded in the

Atlantic The Atlantic Ocean is the second largest of the world's five oceanic divisions, with an area of about . It covers approximately 17% of Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for se ...

, Indian, and

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the cont ...

oceans, including the

Mediterranean Sea The Mediterranean Sea ( ) is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean basin and almost completely enclosed by land: on the east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern Eur ...

. They are found in the deep water benthic environments of continental slopes and

seamount A seamount is a large submarine landform that rises from the ocean floor without reaching the water surface (sea level), and thus is not an island, islet, or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abruptly a ...

s, where they group in pairs or remain solitary. If food is scarce on the seafloor, at night oilfish will rise to the surface to prey on other fish, cephalopods, and crustaceans.

Human use

Fisheries Fishery can mean either the enterprise of raising or harvesting fish and other aquatic life or, more commonly, the site where such enterprise takes place ( a.k.a., fishing grounds). Commercial fisheries include wild fisheries and fish farm ...

targeting oilfish are rare, occurring in small regions of the Atlantic and Pacific through the use of handlines. However, oilfish are common bycatch for fisheries targeting

tuna A tuna (: tunas or tuna) is a saltwater fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae ( mackerel) family. The Thunnini comprise 15 species across five genera, the sizes of which vary greatly, ranging from the bul ...

and

swordfish The swordfish (''Xiphias gladius''), also known as the broadbill in some countries, are large, highly migratory predatory fish characterized by a long, flat, pointed bill. They are the sole member of the Family (biology), family Xiphiidae. They ...

, which employ longlines. Despite their laxative flesh, restaurants sell oilfish meat under the name "white-fish" on account of its texture and flavor. The flesh of oilfish is rich in taste and can be substantially cheaper than that of other fish species, leading to some vendors intentionally mislabelling it as butterfish or

cod Cod (: cod) is the common name for the demersal fish genus ''Gadus'', belonging to the family (biology), family Gadidae. Cod is also used as part of the common name for a number of other fish species, and one species that belongs to genus ''Gad ...

. The consumer may then eat larger servings than recommended, unaware of the laxative effect, and suffer from diarrhea. In Cabo Verde, oilfish is occasionally caught and sold to fishmongers at port, who trade among each other or sell to consumers who request it. While rarely sold at market due to its laxative effects, oilfish is well known among fishmongers and fishermen, and goes by the name Xoba in

Praia Praia (, Portuguese for "beach") is the capital and largest city of Cape Verde.São Vicente.

ParknShop oilfish incident

In January 2007, ParknShop, a supermarket chain in

Hong Kong Hong Kong)., Legally Hong Kong, China in international treaties and organizations. is a special administrative region of China. With 7.5 million residents in a territory, Hong Kong is the fourth most densely populated region in the wor ...

, admitted to selling mislabeled oilfish in their stores. Over 600 people became sick as a result, suffering from stomach pain and diarrhea. A total of 14 complaints were filed against the supermarket chain, leading to an investigation by the

Centre for Food Safety Centre for Food Safety (CFS; ) is the food safety authority of the Hong Kong government. Its mission is to ensure food is safe and fit for consumption through tripartite collaboration among the government, food trade, and consumers. The CFS was ...

. The fish were originally mislabeled in Indonesia, leading to an investigation and allegations of corruption. ParknShop stopped selling the fish, but argued in court that there was no law against the sale of oilfish. The supermarket would later plead guilty to nine charges of inappropriate labelling, and was fined HK$45,000. As a result of the incident, the Centre for Food Safety in Hong Kong published new guidelines on the proper labelling of oilfish and

escolar The escolar, ''Lepidocybium flavobrunneum'', a species of fish in the family Gempylidae, is found in deep (200–885 metres, or 656–2,904 ft) tropical and temperate waters around the world. It is also known as snake mackerel, ' ( ...

to consumers, preventing mislabeling. The

Canadian Broadcasting Corporation The Canadian Broadcasting Corporation (), branded as CBC/Radio-Canada, is the Canadian Public broadcasting, public broadcaster for both radio and television. It is a Crown corporation that serves as the national public broadcaster, with its E ...

in 2007 reported several cases in

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

where mislabelled oilfish was sold at Chinese supermarkets.

References

{{Taxonbar, from=Q297007 Gempylidae Cosmopolitan fish Taxa named by Anastasio Cocco Fish described in 1833

Description

Habitat and ecology

Human use

ParknShop oilfish incident

See also

References