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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
Sinh thái học
Biển; Thuộc về nước lợ gần đáy; Ở đại duơng, biển (Ref. 51243); Mức độ sâu 0 - 330 m (Ref. 92298), usually 0 - 50 m (Ref. 55280). Subtropical; 48°N - 22°N, 91°W - 59°W (Ref. 55280)
Western Atlantic: Massachusetts to southern Florida (USA) and eastern Gulf of Mexico. Also northern Gulf of Mexico (Ref. 26938).
Length at first maturity / Bộ gần gũi / Khối lượng (Trọng lượng) / Age
Maturity: Lm 53.5, range 49 - 60 cm
Max length : 84.0 cm TL con đực/không giới tính; (Ref. 1125)
Small skate, with irregular darker spots and bars on dorsal surface. Translucent area on each side of mid-dorsal ridge on snout (Ref. 26938). Single row of thorns along the midridge of the back (Ref. 6902). Disk with dark brown bars and streaks and some spots. Front edges nearly straight or slightly concave (Ref. 7251).
Found from saltwater parts of estuaries and bays of 330 m (Ref. 26938). Inhabit inshore areas. Prefer waters of 10°-21°C. Feed mainly on decapod crustaceans, bivalves, polychaetes, squids and fishes (Ref. 3824). Breed while inshore (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 capsules are 5.1-8.9 cm long and 3.8-5.7 cm wide (Ref. 41249, 41307, 41301, 41358).
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).
From the work of Libby and Gilbert (1960) (Ref. 51117) and Luer and Gilbert (1985) (Ref. 38742) male and female clearnose skates mate side by side in an upright position (Ref. 49562). Actual copulation occurs when the male bites the caudal margin of the female's pectoral, bends his tail 75 degrees beneath hers and inserts one clasper, flexed ('splayed') medially 90 degrees, into her oviduct (Ref. 49562). A female displays 'back arching' and 'pectoral fin undulations' as precopulatory behavior to attract males (Ref. 49562).
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)
Threat to humans
Harmless
Human uses
Các nghề cá: buôn bán nhỏ; mồi: occasionally
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Estimates based on models
Preferred temperature (Ref.
123201): 9.6 - 25.7, mean 23.5 °C (based on 342 cells).
Phylogenetic diversity index (Ref.
82804): PD
50 = 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00158 (0.00102 - 0.00247), b=3.27 (3.15 - 3.39), in cm total length, based on LWR estimates for this species & (Sub)family-body (Ref.
93245).
Mức dinh dưỡng (Ref.
69278): 3.9 ±0.3 se; based on diet studies.
Generation time: 5.5 ( na - na) years. Estimated as median ln(3)/K based on 1
growth studies.
Thích nghi nhanh (Ref.
120179): thấp, thời gian nhân đôi của chủng quần tối thiểu là 4.5 - 14 năm (K=0.20; Fec assumed to be <100).
Fishing Vulnerability (Ref.
59153): Moderate to high vulnerability (51 of 100).
