Hexanchus griseus
Sixgill Shark [+]

Kingdom: Animalia
Phylum: Chordata
Class: Elasmobranchii
Order: Hexanchiformes
Family: Hexanchidae
Genus: Hexanchus
species: Hexanchus griseus
+ITIS +WoRMS +Conservation Status

Description & Behavior

The bluntnose sixgill shark, Hexanchus griseus (Bonnaterre, 1788), has a number of common names. It is a heavy-bodied, broad-headed shark with a broad, rounded snout and ventral mouth containing 6 rows of blade-like (saw-like), comb-shaped teeth. Anal fin smaller than dorsal fin. Brown or gray above, paler below, with a light stripe along side. Fins have white edges. Fluorescent green eyes. Six gill slits are very long. Body length ranges from 1.5-8 m long.

World Range & Habitat

A deepwater species (surface hunting at night to depths to 2,500 m during the day) of the outer continental and insular shelves and upper slopes. Juveniles may be found close inshore.

Almost circumglobal in tropical and temperate seas. Western Atlantic: North Carolina to Florida (USA) and northern Gulf of Mexico to northern Argentina. Eastern Atlantic: Iceland and Norway to Namibia, including the Mediterranean. Indian Ocean: Madagascar, Mozambique, and South Africa. Western Pacific: eastern Japan to New Zealand and Hawaii. Eastern Pacific: Aleutian Is., Alaska to Baja California, Mexico; also Chile. Highly migratory species.

» GBIF occurrence data in Google Earth [Requirements | Tips] | Ocean Biogeographic Information System (OBIS) [World Map] | [about]

Feeding Behavior (Ecology)

Feeds on a wide range of marine organisms, including other sharks, rays, chimaeras, bony fish, squids, crabs, shrimps, carrion and even seals. Most probably a nocturnal hunter.

Life History

Dioecism, internal (oviduct) fertilization, ovoviviparous. The pups eat any unfertilized eggs and even each other, a behavior known as oviphagy. With other species very few pups in a litter survive until birth due to this form of sibling cannibalism. Litters are very large containing 22-108 pups. Size at birth 60-75 cm. Distinct pairing with embrace during mating.

Ovoviviparous: eggs are retained within the body of the female in a brood chamber where the embryo develops, receiving nourishment from a yolk sac. This is the method of reproduction for the "live-bearing" fishes where pups hatch from egg capsules inside the mother's uterus and are born soon afterward. Also known as aplacental viviparous.

Comments

Visit Shark Angels Website

A valuable food and sports fish, this species seems unable to sustain target fisheries and is taken as bycatch (e.g., in Centrophorus liver oil fisheries now underway over large areas of the Indo-Pacific). Fisheries activity in parts of its range, including the Northeast Pacific, have led to the depletion of regional populations. Liver reported poisonous to eat. Marketed fresh, frozen, or dried salted; also utilized as a source of oil and fishmeal. Not known to have attacked people without provocation though this large shark has been reported to scare a few deep divers.

Listed as Lower Risk (LR/nt) on the IUCN Red List of Threatened Species:

LOWER RISK (LR) - A taxon is Lower Risk when it has been evaluated, does not satisfy the criteria for any of the categories Critically Endangered, Endangered or Vulnerable. Taxa included in the Lower Risk category can be separated into three subcategories:

1. Conservation Dependent (cd). Taxa which are the focus of a continuing taxon-specific or habitat-specific conservation programme targeted towards the taxon in question, the cessation of which would result in the taxon qualifying for one of the threatened categories above within a period of five years.
2. Near Threatened (nt). Taxa which do not qualify for Conservation Dependent, but which are close to qualifying for Vulnerable.
3. Least Concern (lc). Taxa which do not qualify for Conservation Dependent or Near Threatened.

References & Further Research

BioOne ~ CITES ~ Discover Life ~ GBIF ~ Google Scholar ~ ITIS ~ IUCN RedList ~ MarineBio Network ~ NCBI ~ SCIRIS ~ SIRIS ~ Tree of Life Web Project ~ Wikipedia

Bluntnose sixgill shark - Hexanchus griseus - Florida Museum of Natural History

Search the Web for Sixgill Shark » ARKive ~ Ask.com ~ Ask Jeeves ~ bing ~ deviantART ~ dmoz ~ Dogpile ~ Google Images ~ MySpace Images ~ OceanFootage ~ Picsearch ~ StumbleUpon ~ Yahoo! Images ~ YouTube

Feedback?

Citation: Hexanchus griseus, Sixgill Shark - MarineBio.org. Retrieved , from .

Get Involved! Join the MarineBio Society | Partners & Sponsors | Frontline Marine Conservation Support

~ Sharing the wonders of the ocean to inspire conservation, education, research, and a sea ethic ~
MarineBio.org, Inc. is a US 501(c)(3) tax exempt nonprofit organization: info@marinebio.org | +1 (713) 248.2576 PST
All MarineBio Society memberships and donations are tax deductible in the United States.
© 1998-2009 Copyright & Terms of Use. All Rights Reserved. Privacy Policy.
><((((°> Surf with

and Google Chrome >-<°°>-<

Hexanchus griseus Sixgill Shark [+]