इलाज़मौबरांकी (शारक और रेज़) (sharks and rays) >
Hexanchiformes (Frill and cow sharks) >
Hexanchidae (Cow sharks)
Etymology: Hexanchus: hex (Gr.), six; anchus, etymology unclear, perhaps anchos (Gr.), choke or throttle, referring to how six gill openings of H. griseus extend down onto the throat. (See ETYFish); griseus: Medieval Latin for gray, reflecting the French vernacular “Le Griset,” referring to its dark-gray coloration. (See ETYFish).
More on author: Bonnaterre.
Environment: milieu / climate zone / depth range / distribution range
पारिस्थितिकी
समुद्री बाथीड़िमरसल; औशिनोड़िरोमस (Ref. 51243); गहराई सीमा 1 - 2500 m (Ref. 58302), usually 180 - 1100 m (Ref. 45445). Subtropical; 6°C - 10°C (Ref. 125614); 65°N - 48°S, 180°W - 180°E
Circumglobal with patchy distribution and possibly absent from Arctic and Antarctic. Highly migratory species.
Length at first maturity / आकार / वज़न / Age
Maturity: Lm 441.0, range 400 - 482 cm
Max length : 600 cm TL पुल्लिंग / अलिंग; (Ref. 124786); common length : 300 cm TL पुल्लिंग / अलिंग; (Ref. 5217); अधिकतम प्रकाशित वज़न: 590.0 kg (Ref. 27436)
पृष्ठीय रीढ़ (सम्पूर्ण): 0; पृष्ठीय सौफट रेज़ (सम्पूर्ण): 0; गुदा कांटा 0; ऐनल सौफट रेज़: 0. A heavily-bodied, broad-headed sixgill shark, mouth ventral with 6 rows of lower, bladelike, comb-shaped teeth on each side (Ref. 247). Snout broadly rounded, body fusiform (Ref. 6871). Anal fin smaller than dorsal fin (Ref. 6871). Brown or grey above, paler below, with a light stripe along side (Ref. 26346). Fins with white edges (Ref. 6574). Live specimens with fluorescent green eyes (Ref. 6871). Six gill slits are very long (Ref. 35388).
Depth range reported at 0m-2500m (Ref. 125614). A deepwater species of the outer continental and insular shelves and upper slopes (Ref. 6871, 75154), islands, seamounts and mid-ocean ridges (Ref. 125614). Near bottom, occasionally pelagic, adults usually below 91 m (Ref. 58302). Juveniles may be found close inshore (Ref. 6871), while nursery areas are in very shallow waters (Ref. 125614). Found on the bottom by day, moving to the surface at night to feed, and where it may take longlines set for other species (Ref. 45445). Depth distribution related to growth and temperature, with juveniles having most shallow records and from colder, poleward regions (Ref. 58302). Generally occurs at a bottom temperature of 6 to 10°C (Ref. 125614). Feeds on a wide range of marine organisms, including other sharks, rays, chimaeras, bony fish, squids, crabs, shrimps, carrion, and even seals (Ref. 26969). Large sharks (at least 2m) take cetaceans and seals. Viviparous, very large litters of 47-108 pups (Ref. 125614). Give birth to almost 100 young (Ref. 35388). Young and adults may be segregated, with the young using inshore nursery grounds. Possibly long-lived (Ref. 125614). Is a eurytrophic predator that is capable of exploiting a wide range of prey species and habitats (Ref. 26969). A vertical migrant, it may sit on the bottom by day, and rise to the surface at night to feed (Ref. 247). It occurs alone or in groups. Adults are more sensitive to light than the juveniles and less seen in clear shallow waters, but more prevalent at night or areas with dense plankton blooms (Ref. 125614). It is locally common in bycatch and target fisheries for food, fishmeal and oil, and in sports fisheries, but vulnerable to overfishing and requires careful management (Ref. 125614). Marketed fresh, frozen, or dried salted (Ref. 247). Not known to have attacked people without provocation (Ref. 247).
Viviparous, very large litters of 47-108 pups (Ref. 125614). Size at birth 60-75 cm (Ref. 26346). Distinct pairing with embrace (Ref. 205).
Ebert, D.A., S. Fowler and M. Dando, 2021. Sharks of the World: A complete guide. Princeton University Press, 607p. (Ref. 125614)
IUCN Red List Status (Ref. 130435)
Human uses
मात्स्यिकी: व्यापारिक; आखेट मत्स्य: हां
साधन
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इंटरनेट स्रोत
Estimates based on models
Preferred temperature (Ref.
123201): 3.6 - 15.7, mean 8.1 °C (based on 3800 cells).
Phylogenetic diversity index (Ref.
82804): PD
50 = 0.8281 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00117 (0.00066 - 0.00209), b=3.18 (3.01 - 3.35), in cm total length, based on LWR estimates for this species & (Sub)family-body (Ref.
93245).
Trophic level (Ref.
69278): 4.5 ±0.2 se; based on diet studies.
लौटाव (Ref.
120179): निम्न, न्यूनतम जनसंख्या दुगनी होने का समय 4.5 - 14 वर्ष। (Fec= 22-108).
Fishing Vulnerability (Ref.
59153): Very high vulnerability (90 of 100).
Climate Vulnerability (Ref.
125649): Moderate vulnerability (38 of 100).
Nutrients (Ref.
124155): Calcium = 8.75 [2.27, 47.99] mg/100g; Iron = 0.664 [0.163, 2.072] mg/100g; Protein = 19.5 [17.5, 21.5] %; Omega3 = 0.24 [0.10, 0.59] g/100g; Selenium = 79.6 [24.5, 261.1] μg/100g; VitaminA = 3.68 [0.99, 13.90] μg/100g; Zinc = 0.324 [0.155, 0.615] mg/100g (wet weight);
