أشلاق (القروش و الشفانين) (sharks and rays) >
Rajiformes (Skates and rays) >
Rajidae (Skates)
Etymology: Rostroraja: Latin, rostrum = beak + Latin, raja, -ae = a sting ray (Ref. 45335).
Environment: milieu / climate zone / depth range / distribution range
البيئة
بحري القاع; نطاق العمق 1 - 183 m (Ref. 117734), usually 15 - 110 m (Ref. 37039). Subtropical; 14°C - 28°C (Ref. 26938); 30°N - 18°N, 98°W - 80°W
Western Central Atlantic: Florida, USA and the Gulf of Mexico.
Length at first maturity / الحجم / وزن / العمر
Maturity: Lm 53.7, range 48 - 56 cm
Max length : 53.0 cm WD ذكر/ مختلط الجنس; (Ref. 7251); العمر: 9 سنين (Ref. 117734)
Disk diamond-shaped; round dark spot surrounded by pale ring on base of each pectoral fin. (Ref. 26938). No small pale or dark spots on upper surface of disk, but sometimes dark blotches. No scapular spines, 1 middorsal row of spines. Distance from ocellus to eye usually less than or about equal to distance between ocelli. Snout with a clear area on each side (Ref. 7251). Upper surface rich chocolate or coffee brown, translucent on either side fo rostral cartilage. Lower surface plain white (Ref. 6902).
Occur from near shore to 183 m depth at temperatures ranging from 14 to 28° C but it is most common inshore of 91 m at 16-25°C. Young occur in shallow bays. Adults tend to live offshore (Ref. 26938). Adults feed mainly on decapod crustaceans and to a lesser extent on other benthic invertebrates and fishes. 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 6.3 cm long and 3.8 cm wide (Ref. 41359).
Life cycle and mating behavior
Maturities | التكاثر | Spawnings | Egg(s) | Fecundities | Larvae
Oviparous, paired eggs are laid. Embryos feed solely on yolk (Ref. 50449). Distinct pairing with embrace. oung 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
مصائد: غير مهمة تجارياً; طعم: occasionally
أدوات
تقارير خاصة
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مصادر علي الأنترنت
Estimates based on models
Preferred temperature (Ref.
123201): 21.2 - 27.5, mean 24.9 °C (based on 230 cells).
Phylogenetic diversity index (Ref.
82804): PD
50 = 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00269 (0.00124 - 0.00582), b=3.26 (3.09 - 3.43), in cm total length, based on LWR estimates for this Genus-body shape (Ref.
93245).
مستوى غذائي (Ref.
69278): 3.8 ±0.58 se; based on food items.
Generation time: 4.8 ( na - na) years. Estimated as median ln(3)/K based on 2
growth studies.
المرونه (Ref.
120179): منخفض, الحد الزمني الأدني لتضاعف عدد أفراد المجتمع 4.5-14 سنة (k = 0.29; tmax = 9; tm = 5; Fec assumed to be <100).
Fishing Vulnerability (Ref.
59153): Moderate to high vulnerability (45 of 100).
