Roughtail stingray: Difference between revisions
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The roughtail stingray feeds on [[benthic|bottom-dwelling]] [[bony fish]]es, including [[sand lance]] and [[scup]], and [[invertebrate]]s, including [[crustacean]]s, [[polychaete worm]]s, and [[cephalopod]]s. Off [[Virginia]], a major prey item for adult males is the [[shrimp]] ''Upogebia affinis''.<ref name="iucn"/> This species is preyed upon by [[shark]]s, in particular the [[great hammerhead]] (''Sphyrna mokarran''), and other large fishes.<ref name="eagle"/> Known [[parasite]]s of the roughtail stingray include [[flatworm]]s in the genera ''Lecanicephalum'' and ''Polypocephalus''.<ref>{{cite book |title=Interrelationships of the Platyhelminthes |author=Timothy, D., Littlewood, J. and Bray, R.A. |publisher=CRC Press |date=2001 |isbn=0748409033}}</ref> |
The roughtail stingray feeds on [[benthic|bottom-dwelling]] [[bony fish]]es, including [[sand lance]] and [[scup]], and [[invertebrate]]s, including [[crustacean]]s, [[polychaete worm]]s, and [[cephalopod]]s. Off [[Virginia]], a major prey item for adult males is the [[shrimp]] ''Upogebia affinis''.<ref name="iucn"/> This species is preyed upon by [[shark]]s, in particular the [[great hammerhead]] (''Sphyrna mokarran''), and other large fishes.<ref name="eagle"/> Known [[parasite]]s of the roughtail stingray include [[flatworm]]s in the genera ''Lecanicephalum'' and ''Polypocephalus''.<ref>{{cite book |title=Interrelationships of the Platyhelminthes |author=Timothy, D., Littlewood, J. and Bray, R.A. |publisher=CRC Press |date=2001 |isbn=0748409033}}</ref> |
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Like other members of its family, the roughtail stingray is [[ovoviviparous]], in which the developing [[embryo]]s are sustained first by a [[yolk sac]], and then by "uterine milk" produced by the mother.<ref name="eagle"/> Litter sizes range from 2 to 6. Reproductive details differ between the western and eastern Atlantic populations. In the Mediterranean, reproduction occurs year-round with a [[gestation period]] of at least 4 and possibly up to 10 months; females may produce two litters per year, one in June and the other in December. The newborns measure {{convert|8|-|13|cm|in|abbr=on}}. Off the [[United States]], gestation appears to last 9–11 months, with females giving birth once a year in autumn or early winter. The newborns are larger, measuring {{convert|34|-|37|cm|in|abbr=on}}, which could account for the longer gestation period. In the Mediterranean, males mature at {{convert|80|cm|in|abbr=on}} across and females at {{convert|66|-|100|cm|in|abbr=on}} across. In the western Atlantic, males mature at {{convert|130|-|150|cm|in|abbr=on}} across and females at {{convert|140|-|160|cm|in|abbr=on}} across.<ref name="iucn"/><ref name="capape">{{cite journal |author=Capapé, C. |title=New data on the reproductive biology of the thorny stingray, ''Dasyatis centroura'' (Pisces: Dasyatidae) from off the Tunisian coasts |journal=Environmental Biology of Fishes |volume=38 |pages=73–40 |date=1993}}</ref> |
Like other members of its family, the roughtail stingray is [[ovoviviparous]], in which the developing [[embryo]]s are sustained first by a [[yolk sac]], and then by "uterine milk" produced by the mother.<ref name="eagle"/> Litter sizes range from 2 to 6. Reproductive details differ between the western and eastern Atlantic populations. In the Mediterranean, reproduction occurs year-round with a [[gestation period]] of at least 4 and possibly up to 10 months; females may produce two litters per year, one in June and the other in December. The newborns measure {{convert|8|-|13|cm|in|abbr=on}}. Off the [[United States]], gestation appears to last 9–11 months, with females giving birth once a year in autumn or early winter. The newborns are larger, measuring {{convert|34|-|37|cm|in|abbr=on}}, which could account for the longer gestation period. In the Mediterranean, males mature at {{convert|80|cm|in|abbr=on}} across and females at {{convert|66|-|100|cm|in|abbr=on}} across. In the western Atlantic, males mature at {{convert|130|-|150|cm|in|abbr=on}} across and females at {{convert|140|-|160|cm|in|abbr=on}} across.<ref name="iucn"/><ref name="capape">{{cite journal |author=Capapé, C. |title=New data on the reproductive biology of the thorny stingray, ''Dasyatis centroura'' (Pisces: Dasyatidae) from off the Tunisian coasts |journal=Environmental Biology of Fishes |volume=38 |pages=73–40 |date=1993 |doi=10.1007/BF00842905}}</ref> |
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==Relationship to humans== |
==Relationship to humans== |
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Revision as of 07:39, 25 February 2010
| Roughtail stingray | |
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| Roughtail stingray at the McGrail Bank, Gulf of Mexico | |
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| Species: | D. centroura
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| Binomial name | |
| Dasyatis centroura (Mitchill, 1815)
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| Range of the roughtail stingray | |
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Dasybatus marinus Garman, 1913 | |
The roughtail stingray, Dasyatis centroura, is a species of stingray in the family Dasyatidae. It is the largest stingray in the Atlantic Ocean, measuring up to 2.2 m (7.2 ft) across and weighing 300 kg (660 lb), and can be distinguished by its long, slender tail studded with rows of thorns.[2] The taxonomy of the roughtail stingray is not fully resolved, with the disjunct northwestern Atlantic, southwestern Atlantic, and eastern Atlantic populations differing in life history and possibly representing a complex of different species.[1] Its specific epithet centroura is derived from the Greek centoro, meaning "pricker".[2]
Distribution and habitat
This stingray is broadly but discontinuously distributed in the subtropical marine waters of the Atlantic Ocean. In the western Atlantic, it occurs from the Georges Bank and Cape Cod, Massachusetts, to Florida, the Bahamas, and the northeastern Gulf of Mexico. Additionally, there are recent reports of this species off Uruguay, Brazil, and Argentina, though they may represent a different species. The taxonomic status of the eastern Atlantic populations are also uncertain; there the roughtail stingray occurs from the southern Bay of Biscay to Angola, including the Mediterranean Sea, Madeira, and the Canary Islands. A single record from Quilon, India was likely a misidentification.[1]
The roughtail stingray has been reported at depths of 3-270 meters (10–890 ft), though it is most common at 15-50 meters (50–160 ft).[3] It prefers water temperatures of 15–26 °C (59–79 °F). This species is usually found over sandy and muddy bottoms; in warmer months it enters coastal waters, bays, and estuaries.[2]
Description
The roughtail stingray has a rhomboid pectoral fin disk with straight to gently sinusoidal front margins, sharply rounded to angular corners, and a moderately long, broad-angled snout. The mouth is arched, with an indentation at the symphysis and six papillae on the floor.[4] The teeth have tetragonal bases and have flattened crowns in females and juveniles and pointed ones in mature males. There are 7 functional tooth rows in the upper jaw and 12-14 rows in the lower. The most distinctive feature of the roughtail stingray is its whip-like tail, which measures some 2.5 times the length of the disk and bears many rows of small thorns.[2] There are 1-2 (rarely 3) long, saw-toothed spines on the upper surface of the tail, and a low fin fold on the ventral surface.[5]
Individuals under 51 cm (20 in) across lack dermal denticles; larger specimens develop denticles on the snout, behind the spiracles, on the aft corner of the disk, and at the base of the tail, as well as large tubercles or bucklers (flat-based thorns) on and around the dorsal midline and the tail.[4] The coloration is dark brown to olive above and white below without darker fin margins; the tail is black behind the spine. One of the largest stingrays, the roughtail stingray can attain a disk width of 2.2 m (7.2 ft) and a weight of 300 kg (660 lb).[2] Females are larger than males.[6]
Biology and ecology
The roughtail stingray feeds on bottom-dwelling bony fishes, including sand lance and scup, and invertebrates, including crustaceans, polychaete worms, and cephalopods. Off Virginia, a major prey item for adult males is the shrimp Upogebia affinis.[1] This species is preyed upon by sharks, in particular the great hammerhead (Sphyrna mokarran), and other large fishes.[2] Known parasites of the roughtail stingray include flatworms in the genera Lecanicephalum and Polypocephalus.[7]
Like other members of its family, the roughtail stingray is ovoviviparous, in which the developing embryos are sustained first by a yolk sac, and then by "uterine milk" produced by the mother.[2] Litter sizes range from 2 to 6. Reproductive details differ between the western and eastern Atlantic populations. In the Mediterranean, reproduction occurs year-round with a gestation period of at least 4 and possibly up to 10 months; females may produce two litters per year, one in June and the other in December. The newborns measure 8–13 cm (3.1–5.1 in). Off the United States, gestation appears to last 9–11 months, with females giving birth once a year in autumn or early winter. The newborns are larger, measuring 34–37 cm (13–15 in), which could account for the longer gestation period. In the Mediterranean, males mature at 80 cm (31 in) across and females at 66–100 cm (26–39 in) across. In the western Atlantic, males mature at 130–150 cm (51–59 in) across and females at 140–160 cm (55–63 in) across.[1][6]
Relationship to humans
Though not aggressive, the roughtail stingray can inflict a painful wound with its poisonous tail spine and should be treated with caution.[5] This species is damaging to shellfish banks. Its wings are sold for human consumption fresh, smoked, or dried and salted, and it is also utilized for fish meal and liver oil.[3] The roughtail stingray has been assessed globally as of Least Concern by the World Conservation Union. This species is not targeted by fisheries in the northwestern Atlantic and the population there is stable; it is taken as bycatch in trawls and longlines but the impact is minimal. However, in the southwestern Atlantic, this species is thought to have declined under heavy fishing pressure; it is caught via demersal trawls, longlines, gillnets, and hook-and-line, and there is increasing commercial interest in utilizing stingrays for minced fish products. In the Mediterranean, this species is also suspected to have declined, due to bycatch from artisanal fisheries, gillnets, bottom set longlines, handlines, and benthic trawls. Thus, the southwestern Atlantic and Mediterranean populations are tentatively considered to be Near Threatened, pending more specific information.[1]
References
- ^ a b c d e f Template:IUCN2008
- ^ a b c d e f g Eagle, D. Biological Profiles: Roughtail Stingray. Florida Museum of Natural History Ichthyology Department. Retrieved on March 23, 2009.
- ^ a b Froese, Rainer; Pauly, Daniel (eds.) (2009). "Dasyatis centroura" in FishBase. March 2009 version.
- ^ a b McEachran, J.D. and Fechhelm, J.D. (1998). Fishes of the Gulf of Mexico: Myxiniformes to Gasterosteiformes. University of Texas Press. ISBN 0292752067.
{{cite book}}: CS1 maint: multiple names: authors list (link) - ^ a b Bigelow, H.B. and Schroeder, W.C. (1953). Fishes of the Gulf of Maine: Fishery Bulletin 74. The Blackburn Press. ISBN 1930665601.
{{cite book}}: CS1 maint: multiple names: authors list (link) - ^ a b Capapé, C. (1993). "New data on the reproductive biology of the thorny stingray, Dasyatis centroura (Pisces: Dasyatidae) from off the Tunisian coasts". Environmental Biology of Fishes. 38: 73–40. doi:10.1007/BF00842905.
- ^ Timothy, D., Littlewood, J. and Bray, R.A. (2001). Interrelationships of the Platyhelminthes. CRC Press. ISBN 0748409033.
{{cite book}}: CS1 maint: multiple names: authors list (link)