Owston's White-eyed Shark (Centroscymnus Owstonii)

2023 Author: Molly Page | [email protected]. Last modified: 2023-11-27 22:49

Names: Owston's white-eyed shark, Roughskin dogfish.

Description

The holotype of the white-eyed Ouston shark (male, 79 cm long) was caught off the coast of Japan (Honshu Island) and is now in the Museum of Comparative Zoology (Harvard University, USA).

The short-spiked white-eyed shark has a stocky body without a strong taper towards the head or tail. The head is flat, blunt-pointed. The muzzle is of medium length. The mouth is also small. The lips are fleshy. The eyes are of medium size, oval. The folds of the upper lip are short.

Dorsal fins are approximately the same size. In front of each of them there is a small, sturdy thorn. The second dorsal fin is located very close to the caudal fin. The pectoral fins are large, located in front of the first dorsal fin. The pelvic fins are located slightly in front of the second dorsal fin. The anal fin is missing. The tail fin has a structure characteristic of the genus of white-eyed sharks: a small but pronounced lower lobe and a wide upper lobe with a "shark" pennant. Plakoid scales are pointed, large, oval in shape. On some parts of the body, ribbed placoid scales are found.

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Teeth

The teeth of the upper jaw are sagittal (narrow, slightly widening towards the end and have one central apex). The lower teeth are wide and triangular in shape. The teeth of the lower jaw have one apex, beveled from the edge of the mouth to the center of the mouth.

Color

The color is solid, monochromatic, usually black or slightly brownish.

The size

Adult males are smaller than females, their body length is 70-79 cm. The average body length of females is 82-105 cm. The largest specimen of the white-eyed Ouston shark caught had a body length of 121 cm. For newborn sharks, the body length is 25-30 cm.

Area

The distribution of Owston's white-eyed sharks includes a small part of the eastern (in the Azores and Canary Islands, Madeira, off the coast of Guinea-Bissau, Namibia and South Africa) and the western Atlantic (off the coast of Argentina and in the Gulf of Mexico). Also, sharks of this species live in the Pacific Ocean along the entire southern coast of Australia, near New Zealand (especially in the area of Severny Island), the southern coast of Japan, about. Sala-i-Gomez and Easter Island. Scientists believe that now known habitats constitute only part of the total habitat of sharks of this species.

Countries where Ouston's white-eyed sharks live: Namibia, South Africa, USA, Argentina, Japan, New Zealand, Australia, Senegal, Guinea-Bissau, Gambia.

Habitat

They live in the seas of tropical, subtropical and temperate climatic zones at a depth of 100 to 1500 meters. Most often found on high or medium continental slopes.

Nutrition

White-eyed short-thorn sharks feed mainly on bottom fish and cephalopods. Sometimes sharks of this species prey on invertebrates.

Behavior

Sharks lead a bottom life. Mobile deep-sea predators. It has been observed that Ouston's white-eyed sharks can migrate from their habitats if they become fishing grounds.

Social structure

Ouston's white-eyed sharks lead a solitary lifestyle, meeting each other for breeding or hunting (cannibalism is characteristic).

Enemies

Large bottom predatory fish, including other sharks.

Reproduction

Ovoviviparous. The female produces offspring once a year.

Pregnancy

Pregnancy lasts presumably about a year.

Offspring

One litter can contain from 16 to 28 sharks. Newborns have a body length of 27-30 cm. Cubs are born sufficiently developed to immediately begin an independent life.

Related article White-eyed Spiny Shark (Centroscymnus coelolepis)

Benefits for humans

The species is not a commercial species. The meat of the short-thorned white-eyed shark is rich in mercury, so it is not eaten. However, caught sharks of this species are still used as a source for the manufacture of fishmeal and for obtaining squalene.

Harm to humans

It does not pose a danger to humans, since it lives at great depths. However, fishermen should beware of the spines in front of the dorsal fins (similar to the “thorns” of a perch), which can injure their hands.

Population

At present, there is no threat of extinction for sharks of this species, due to minimal human intervention (no fishing is carried out).

Conservation status

To date, this species has the status of “not causing concern”, conservation measures have not been developed. Some experts believe that due to low reproduction and slow growth, it is likely that Ouston's white-eyed sharks may soon receive a higher conservation status.

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