Elasmobranchii (sharks and rays) > Rajiformes
(Skates and rays) > Rajidae
Etymology: Amblyraja: Greek, amblys = darkness + Latin, raja, -ae = ray (Raja sp.) (Ref. 45335).
Environment / Climate / Range
Marine; bathydemersal; depth range 140 - 2500 m (Ref. 50610), usually 300 - 1500 m (Ref. 3167). Deep-water; -1°C - ? (Ref. 3167); 82°N - 50°S
Length at first maturity / Size / Weight / Age
Maturity: Lm ?, range 94 - ? cm
Max length : 106 cm TL male/unsexed; (Ref. 6871)
Morphology | Morphometrics
Grey-brown with large dark blotches (Ref. 26346). Tail very short (Ref. 26346). Mid-dorsal row of stout thorns which extend from nuchal region to first dorsal fin. Thorns close posterior to the pelvic girdle larger than along the tail (Ref. 6902). Upper surface dark mouse gray, dark blue gray or dark brown with small rounded spots. Lower surface white and sooty in variable patterns (Ref. 6902).
Northeast Atlantic: Spitsbergen to the Greenland-Iceland-Faroe-Shetland Ridge to northern Norway. Northwest Atlantic: Davis Strait between southwestern Greenland and Canada. Southeast Atlantic: southern tip of South Africa (Ref. 6871). Eastern Indian Ocean: off southern Australia (Ref. 6871). Southwest Pacific: New Zealand (Ref. 6871). Eastern Pacific: Costa Rica, Panama, Colombia, and Ecuador (Ref. 6871).
Found on the lower continental slope (Ref. 6871). Benthic (Ref. 58426). Feed on all kinds of bottom animals (Ref. 3167). Prefer polar temperatures from hatching to maturity and eggs are incubated successfully and regularly in water as cold as 0°C (Ref. 6902). Oviparous. Distinct pairing with embrace. Young may tend to follow large objects, such as their mother (Ref. 205). Eggs are oblong capsules with stiff pointed horns at the corners deposited in sandy or muddy flats (Ref. 205). Egg capsule measures 81-125 mm long and 50-80 mm wide (Ref. 41251).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Oviparous, paired eggs are laid. Embryos feed solely on yolk (Ref. 50449). Distinct pairing with embrace. Young may tend to follow large objects, such as their mother (Ref. 205).
McEachran, J.D. and K.A. Dunn, 1998. Phylogenetic analysis of skates, a morphologically conservative clade of elasmobranchs (Chondrichthyes: Rajidae). Copeia 1998(2):271-290. (Ref. 27314)
IUCN Red List Status (Ref. 96402)
CITES (Ref. 94142)
Threat to humans
Fisheries: of no interest
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingMass conversion
Estimates of some properties based on models
Phylogenetic diversity index (Ref. 82805
= 0.5010 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00302 (0.00135 - 0.00677), b=3.21 (3.03 - 3.39), based on LWR estimates for this (Sub)Family-body shape (Ref. 93245
Trophic Level (Ref. 69278
): 4.3 ±0.5 se; Based on diet studies.
Resilience (Ref. 69278
): Low, minimum population doubling time 4.5 - 14 years (Fec assumed to be <100).
Vulnerability (Ref. 59153
): High vulnerability (57 of 100) .