أشلاق (القروش و الشفانين) (sharks and rays) >
Rajiformes (Skates and rays) >
Rajidae (Skates)
Etymology: Leucoraja: Greek, leykos = white + Latin, raja = a fish, Raja sp. (Ref. 45335).
More on author: Mitchill.
Environment: milieu / climate zone / depth range / distribution range
البيئة
بحري القاع; محيطية (Ref. 51243); نطاق العمق 10 - 914 m (Ref. 106604). Temperate; 49°N - 33°N, 78°W - 59°W (Ref. 55277)
Western Atlantic: southern Gulf of St. Lawrence and Nova Scotia in Canada to North Carolina, USA.
Length at first maturity / الحجم / وزن / العمر
Maturity: Lm 37.5, range 32 - 43 cm
Max length : 62.0 cm TL ذكر/ مختلط الجنس; (Ref. 106604); العمر: 12 سنين (Ref. 88929)
Usually on sandy or gravelly bottoms from shoal waters to 90 m depth (Ref. 7251), with temperature range of 1.2-21°C. Benthic (Ref. 5951). Mostly inactive during daylight, but active under dark conditions (Ref. 10807). Feeds on bottom-dwelling organisms such as crabs, shrimps, polychaetes, sea squirts, mollusks, squids and bony fishes (Ref. 27549). 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 capsules are 4.6-6.3 cm long and 2.7-4.8 cm wide, about 10-35 eggs are laid annually (Ref. 41250). Possesses an electric organ located in the tail region (Ref. 10807). Electric organ discharge (EOD) activity is intermittent (Ref. 10011) and seemed more frequent during dark periods (Ref. 10808). The individual EOD of this species is monophasic, head-negative, and lasts 70 ms (Ref. 10011).
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. 130435)
استخدامات بشرية
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مصادر علي الأنترنت
Estimates based on models
Preferred temperature (Ref.
123201): 3.3 - 11.9, mean 6.8 °C (based on 97 cells).
Phylogenetic diversity index (Ref.
82804): PD
50 = 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00282 (0.00248 - 0.00320), b=3.22 (3.18 - 3.26), in cm total length, based on LWR estimates for this species (Ref.
93245).
مستوى غذائي (Ref.
69278): 3.6 ±0.1 se; based on diet studies.
المرونه (Ref.
120179): منخفض, الحد الزمني الأدني لتضاعف عدد أفراد المجتمع 4.5-14 سنة (K=0.29-0.35; tm=4.5; Fec=10; tmax=12).
Fishing Vulnerability (Ref.
59153): Moderate to high vulnerability (50 of 100).
Climate Vulnerability (Ref.
125649): Very high vulnerability (90 of 100).
Nutrients (Ref.
124155): Calcium = 8.66 [1.21, 152.16] mg/100g; Iron = 0.286 [0.027, 3.412] mg/100g; Protein = 15.9 [13.9, 17.9] %; Omega3 = 0.79 [0.34, 1.99] g/100g; Selenium = 11.9 [2.5, 63.8] μg/100g; VitaminA = 6.64 [0.51, 72.57] μg/100g; Zinc = 0.394 [0.028, 4.300] mg/100g (wet weight);
