The distribution of bull rays is not well-defined, but most observations report its range within tropical and subtropical waters of the Eastern Atlantic Ocean, between 44°N - 35°S, 19°W - 36°E, off the coast of Portugal down to the Saldanha Bay, South Africa. Bull rays have also been sighted in the Mediterranean Sea, the Black Sea, off the Canary Islands and Madeira, and in the Indian Ocean, off the coast of Kenya.
Biogeographic Regions: palearctic (Native ); ethiopian (Native ); oceanic islands (Native ); indian ocean (Native ); atlantic ocean (Native ); mediterranean sea (Native )
Sexual development in bull rays begins when individuals reach approximately 100 cm in length. Disc-width at birth ranges from 250 mm to 270 mm. Total length at birth ranges from 530 mm to 560 mm, and weight ranges from 310 g to 345 g. Male and female development is divided into three stages: juvenile (I), subadult (II) and adult (III). For males, growth stage is noted by the shape and size of their tubercles. In Stage I, the anterior edge of the orbital area (the area above the eye) is smooth. In Stage II, tubercles form in the orbital area and slightly protrude above the eye. In Stage III, the tubercles are prominent and fully developed, with a cone-like shape. Juvenile and subadult males, stage I and II, respectively, have short, uncalcified and flexible claspers along with undeveloped, thread-like testes and genital ducts. During stage II, clasper grows quickly. As adults (stage III), claspers are elongated, calcified, and rigid. Adult males have fully developed and fully functional claspers, testes, and genital ducts. Female sexual development is marked by changes in appearance of their internal reproductive organs. During stage I, ovaries are white with microscopic oocytes and indistinct nidamental glands. During stage II, oocytes are translucent and the genital ducts are thread-like. During Stage III, the genital duct is fully developed.
Embryonic development in bull rays occurs through a reproductive process known as ovoviviparity. Eggs are fertilized internally, and embryos develop in egg cases while receiving nourishment from yolk sacs until they hatch out from the thin-walled membranes and continue development in the uterus. While in the uterus, embryos absorb nourishment through a combination of enriched nutrients supplied by mucus, fat, and protein from the uterine lining. This nutritional secretion is termed histotroph or “uterine milk,” and is ingested through a developing pup's mouth and spiracles. This type of nutrient supply facilitates the birth of large offspring. Gestation lasts about six months, with 3 to 7 pups produced in each litter.
Bull ray population size and trends are unknown, making it difficult to determine the potential conservation needs of this species. Bull rays are classified as “data deficient” on the IUCN's Red List of Threatened Species, indicating there is insufficient data to adequately evaluate its conservation status.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: data deficient
Like most members of Chondrichthyes, bull rays have a lateral line, which they use to perceive their immediate environment. They also have nares for olfactory perception and eyes. Like other elasmobranchs, bull rays possess small electrical sensing organs, known as ampullae of Lorenzini, which form a subcutaneous electrosensory detection system. Located on the underside of the snout, the ampullae of Lorenzini detect weak electrical currents generated by the muscular contractions of their prey. Using this organ system, bull rays can detect prey buried several centimeters below the seafloor.
Communication Channels: visual ; tactile ; chemical ; electric
Perception Channels: visual ; tactile ; chemical ; electric
Bull rays have sharp barbs on their tails, which can be troublesome for humans. Bull rays may rest on sandy bottoms within the intertidal zone, where humans may accidentally encounter them. Otherwise, there are no known adverse effects of bull rays on humans.
Negative Impacts: injures humans (bites or stings)
Although they are occasionally pursued by humans, bull rays are very rare and not commonly caught by fisherman. Otherwise, there are no known positive effects of bull rays on humans.
Bull rays are shallow water predators in soft-bottomed environments of the neritic zone. They forage and feed upon benthic fish and small invertebrates, and in doing so, are important secondary and tertiary consumers within their environment. Rays excavate the soft bottoms of the sea floor while foraging for invertebrate prey. Disturbed sediments are rapidly recolonized by macrofauna and their larvae. Thus, foraging and predatory activities create habitat diversity and environmental heterogeneity.
Bull rays are host to numerous endoparasites, including trematode flatworms, monogenean flatworm, and ascarid worm.
Ecosystem Impact: creates habitat
Commensal/Parasitic Species:
Bull rays are carnivores that feed on benthic invertebrates. Important food items include brachyuran crabs, hermit crabs, prawns, and other bottom-dwelling crustaceans. They also feed on gastropod molluscs, bivalves, and small squids. A predominant prey item for the bull ray in South Africa is the sand-burrowing surf clam.
Animal Foods: mollusks; aquatic crustaceans; other marine invertebrates
Primary Diet: carnivore (Molluscivore )
Bull rays are predominantly found in brackish coastal waters and prefer warm waters from the surf zone, which varies from one location to the next, to depths up to 150 m deep. They are commonly found in estuaries and lagoons, due to the abundance of prey in these habitats.
Range depth: surf zone to 150 m.
Habitat Regions: temperate ; tropical ; saltwater or marine
Aquatic Biomes: pelagic ; benthic ; reef ; coastal ; brackish water
Other Habitat Features: estuarine ; intertidal or littoral
There is little information available regarding the average lifespan of bull rays. Commonly, rays grow and mature slowly, and bull rays have been known to live up to 14 years in the wild.
Range lifespan
Status: wild: 14 (high) years.
Range mass: 5.3 to 116 kg.
Range length: 0.74 to 1.48 m.
Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry
Sexual Dimorphism: female larger; sexes shaped differently
Humans are a significant predator of bull rays. In addition, they are often caught in trawl nets as bycatch by shrimp fishermen, and in shark exclusion nets deployed at coastal beaches along South Africa. Natural predators include great hammerhead sharks and various pinniped species, such as South African fur seals.
Known Predators:
Like most elasmobranchs, bull rays are polygynandrous and mate with different partners throughout breeding season. While little documentation exists on the mating behaviors of elasmobranchs in general, a few species of rays and skates have been observed copulating in the wild. Pre-copulatory behavior occurs in many species of rays, and is illustrated by the scars and wounds left on the dorsal surface of females. In male eagle rays, precopulatory behaviors include diving upon and biting the backs of females during courtship. The male inserts a pair of modified anal fins called claspers into the female to begin coitus. Copulation may last up to several hours. It is believed that female receptivity is dependent on hormonal status.
Mating System: polygynandrous (promiscuous)
Rays in the family Myliobatidae, which includes bull rays, reproduce on a yearly cycle that ranges begins in spring and ends in fall. Gestation in bull rays lasts approximately 6 months and results in 3 to 7 pups per litter. Most individuals become sexually mature by 4 to 6 years after birth.
Breeding season: Mating season begins in spring and ends in fall.
Range number of offspring: 3 to 7.
Average gestation period: 6 months.
Average time to independence: 0 minutes.
Range age at sexual or reproductive maturity (female): 4 to 6 years.
Range age at sexual or reproductive maturity (male): 4 to 6 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); ovoviviparous
Females carry developing pups and nourish them with histotroph until they are born. There is no documentation of post-birth parental care in the family Myliobatidae. Bull ray pups are born fully developed and independent, able to fend for themselves.
Parental Investment: pre-hatching/birth (Provisioning: Female, Protecting: Female)
Die Bulrog (Pteromylaeus bovinus) is 'n vis wat aan die hele kuslyn van Suid-Afrika voorkom. Dit is sjokoladebruin met bleekgrys dwarsstrepe bo-op en wit onder. Dit word 1.8m breed en 85 kg swaar. Die vis is 'n bodembewoner in vlakwater maar spring ook uit die water. In Engels staan diit ook bekend as Bullray.
Die Bulrog (Pteromylaeus bovinus) is 'n vis wat aan die hele kuslyn van Suid-Afrika voorkom. Dit is sjokoladebruin met bleekgrys dwarsstrepe bo-op en wit onder. Dit word 1.8m breed en 85 kg swaar. Die vis is 'n bodembewoner in vlakwater maar spring ook uit die water. In Engels staan diit ook bekend as Bullray.
El bisbe (Pteromylaeus bovinus (Geoffroy Saint-Hilaire, 1817)), dit també bonjesús, milà, monja, xutxo[1] , és un peix cartilagini de la família Myliobatidae.[2]
El seu aspecte és semblant al de l'àguila de mar, de la qual difereix per un musell més pronunciat i en punta i un més gran dimensió (pot abastar 2,5 metros de llarg i 80 quilos de pes). El seu color és marró clar al dors i blanc al ventre; els exemplars joves són caracteritzadts per set o vuit estries dorsals que desapareixen quan atenyen l'edat adulta. Les seves aletes dorsals són situades a la mateixa altura de les pèlviques.
És àmpliament present en l'Oceà Atlàntic oriental, en l'Oceà Indi sudoccidental, en el Mar Mediterrani i en la Mar Negra. La seva presència a l'Atlàntic és a vegades controvertida encara que amb tota probabilitat és confirmada a les costes del Marroc, Sàhara Occidental, Senegal, Illes Canàries, Madeira, Mauritània, Gàmbia. Guinea i Guinea Bissau.
Éss una espècie pròpia de les aigües temperades i tropicals així com de llacunes i estuaris fluvials.
Viu en grupets. La seva alimentació es compon sobretot de crustacis i Mol·luscs del fons marí. Es tracta d'animal ovovivípar; la femella pareix una ventrada de tres o quatre petits després d'una gestació molt variable llarga d'entre cinc i dotze mesos.
El bisbe (Pteromylaeus bovinus (Geoffroy Saint-Hilaire, 1817)), dit també bonjesús, milà, monja, xutxo , és un peix cartilagini de la família Myliobatidae.
Der Gestreifter Adlerrochen (Aetomylaeus bovinus, Syn.: Pteromylaeus bovinus) ist eine Rochenart, die küstennah im östlichen Atlantik in Tiefen von 10 bis 150 Metern vorkommt. Das genaue Verbreitungsgebiet reicht von Madeira über Portugal, Marokko und die Kanarischen Inseln bis Südafrika, geht dort um das Kap der Guten Hoffnung bis zum südlichen Mosambik und erreicht damit den äußersten Südwesten des Indischen Ozeans. Außerdem kommt er im Mittelmeer vor, wo er inzwischen aber selten ist.
Der Gestreifte Adlerrochen erreicht mit seinem langen, peitschenartigen Schwanz eine Länge von maximal 2,50 Metern und ein Maximalgewicht von 83 kg, bleibt für gewöhnlich aber bei einer Länge von 1,50 Meter. Seine lange, abgeflachte und abgerundete Schnauze erinnert entfernt an einen Entenschnabel, weshalb er oft auch Entenschnabelrochen genannt wird. Ober- und Unterkiefer sind mit sieben Reihen von flachen Zähnen besetzt. Der Kopf ist groß, die flügelähnlichen, großen Brustflossen enden in abgerundeten Spitzen. Gestreifte Adlerrochen sind oberseits grünbraun bis hellbraun mit 7 bis 8, seltener 9 helle blaugraue Streifen. Die Bauchseite ist weiß. Kopf, Rumpf und Brustflossen ergeben eine rautenähnliches Körperprofil. Eine Schwanzflosse fehlt. Während die primitiven Geigenrochen, sowie die Sägerochen und die Zitterrochenartigen sich wie die meisten Haie durch Stammschlängeln des Körpers und der Schwanzflosse fortbewegen und die Echten Rochen sich durch wellenförmige Bewegungen ihrer großen Brustflossen fortbewegen, schlagen Gestreifte Adlerrochen wie alle anderen Adlerrochen ähnlich wie Vögel mit ihren Flügeln mit den vergrößerten Brustflossen.
Der Gestreifte Adlerrochen lebt küstennah allein, zeitweise auch in kleinen Gruppen. Er ernährt sich vor allem von bodenbewohnenden Krebstieren und Weichtieren. Wie alle Adlerrochen ist er ovovivipar. Die drei bis sieben Jungrochen werden im Herbst geboren.
Der Gestreifter Adlerrochen (Aetomylaeus bovinus, Syn.: Pteromylaeus bovinus) ist eine Rochenart, die küstennah im östlichen Atlantik in Tiefen von 10 bis 150 Metern vorkommt. Das genaue Verbreitungsgebiet reicht von Madeira über Portugal, Marokko und die Kanarischen Inseln bis Südafrika, geht dort um das Kap der Guten Hoffnung bis zum südlichen Mosambik und erreicht damit den äußersten Südwesten des Indischen Ozeans. Außerdem kommt er im Mittelmeer vor, wo er inzwischen aber selten ist.
Golub ćukan (lat Pteromylaeus bovinus) riba je iz reda pravih raža (lat. Rajiformes), porodice morskih golubova (lat. Myliobatidae). Naraste do 250 cm duljine i 83 kg težine. Tijelo mu je spljošteno kao i kod svih goluba, s izduljenim bočnim perajama, kao krilima koje završavaju oštro. Ima izduljenu njušku, ravnu, koja podsječa na pačji kljun, u ustima ima 7 redova ravnih zuba . Svijetlo smeđe je boje, sa desetak sivo-plavih pruga po leđima. Živi na dubinama do 150 m u tropskim i toplijim morima, a hrani se pridnenim školjkašima i rakovima. Živi većino sam, a ponekad i manjim grupama. rep mu je dugačak i oblika biča. Uz sam početak repa, u kožnoj ovojnici se nalazi velika i dobro razvijena bodlja. Bodlja je od vazodentina, tvrdog, kosti sličnog materijala. Duž bodlje prostire se ventrolateralna žlijezdana udubina u kojioj se nalazi otrovno žljezdano tkivo, iz kojeg se otrov ispušta u bodlju. Pošto voli toplija mora, u Jadranu nije čest, najčešće se uhvati na južnom dijelu. Cijenjen je u prehrani.
Golub ćukan je riba koja prebiva po cijelom istočnom dijelu Atlantika, od Portugala do Angole, a također i oko juga Afrike, te u Indijskom okeanu oko Mozambika
Golub ćukan (lat Pteromylaeus bovinus) riba je iz reda pravih raža (lat. Rajiformes), porodice morskih golubova (lat. Myliobatidae). Naraste do 250 cm duljine i 83 kg težine. Tijelo mu je spljošteno kao i kod svih goluba, s izduljenim bočnim perajama, kao krilima koje završavaju oštro. Ima izduljenu njušku, ravnu, koja podsječa na pačji kljun, u ustima ima 7 redova ravnih zuba . Svijetlo smeđe je boje, sa desetak sivo-plavih pruga po leđima. Živi na dubinama do 150 m u tropskim i toplijim morima, a hrani se pridnenim školjkašima i rakovima. Živi većino sam, a ponekad i manjim grupama. rep mu je dugačak i oblika biča. Uz sam početak repa, u kožnoj ovojnici se nalazi velika i dobro razvijena bodlja. Bodlja je od vazodentina, tvrdog, kosti sličnog materijala. Duž bodlje prostire se ventrolateralna žlijezdana udubina u kojioj se nalazi otrovno žljezdano tkivo, iz kojeg se otrov ispušta u bodlju. Pošto voli toplija mora, u Jadranu nije čest, najčešće se uhvati na južnom dijelu. Cijenjen je u prehrani.
Aetomylaeus bovinus, also known as the bull ray, duckbill ray,[3] or duckbill eagle ray,[1] is a species of large stingray of the family Myliobatidae found around the coasts of Europe and Africa.[2]
The species is ovoviviparous and reach sexual maturity at 4 to 6 years old. With a low fecundity of three to four pups per litter and a long gestation of 6 to 12 months (depending on the geographical zone), this species have a very sensitive life history. Very little is known concerning the ecology and behavior of A. bovinus, however it is part of the coastal marine megafauna, with a maximum length of 222 cm (87.4 in) and 116 kg (225.7 lbs), bull rays can be considered as giants of the shallow waters. Their maximum length and very narrow depth range of 0 to 30 m exposes them to various threats. Indeed, large-body, shallow-water species are at greatest risk of threats. Bull ray appears to be extremely rare throughout the Mediterranean region and its current population trend is highly suspected to be decreasing.
This fish is named the bull ray because of the shape of its head and it is sometimes called the duckbill ray in South Africa for its long, flat, round snout.[4] Females are larger and heavier than males.
Bull rays are "bentho-pelagic" feeders, which means that they feed on the sea floor and the water column. They feed on various invertebrates including crabs, hermit crabs, squids, prawns, gastropod molluscs and bivalve molluscs. They often cause damage to clam and oyster farms.[5]
Aetomylaeus bovinus is facing various and numerous threats, from fisheries to habitat degradation. As it is a benthic and semi-pelagic feeder, it is by-catch by a large game of industrial or artisanal fishing gear, especially pelagic trawling, bottom trawling, trammel nets, gill nets and spearfishing. Little information is available concerning this species in Africa, however old literature refers to a discard of 900 tones per year of bull rays by-caught by shrimp trawlers on the West African coast in 1988 during their late juvenile and sub/adult phase.
On a global scale, Aetomylaeus bovinus is classified as Critically Endangered. The bull ray is now part of the 53% of elasmobranchs native to the Mediterranean Sea that are at risk of extinction and require urgent action to conserve their population and habitats. Bull rays appear to be extremely rare throughout the Mediterranean region and their current population trend is highly suspected to be decreasing (by 80% during the last 45 years according to IUCN). There are currently no species-specific measures in place. Much research is required on the bull ray's population, size, trend, habitat, ecology, and threats. In order to protect the bull ray, its habitat needs to be protected, its harvest monitored and managed, and implementation of education and awareness programs could be beneficial.
The full distribution of the bull ray is uncertain but it is known to be found in the Mediterranean Sea,[5] the Black Sea, the eastern Atlantic Ocean between Portugal and Guinea, the Atlantic from north of Saldanha Bay in western South Africa and round the rest of the South African coast into the Indian Ocean up to Maputo Bay in southern Mozambique, also Zanzibar and Kenya.[4][6]
It is found between the surf zone and depths of 65 m (213 ft) or more and also enters estuaries and lagoons.[4] It frequents both the bottom and the surface and sometimes leaps from the water.[4]
The population size, trend, habitat, ecology and dynamic of the species remain unknown, however, like many members of the family Myliobatidae, Aetomylaeus bovinus is a potential migratory species.
{{cite journal}}: CS1 maint: multiple names: authors list (link) {{cite web}}: CS1 maint: url-status (link) Aetomylaeus bovinus, also known as the bull ray, duckbill ray, or duckbill eagle ray, is a species of large stingray of the family Myliobatidae found around the coasts of Europe and Africa.
La raya tigre o pez obispo, también llamado rata o chucho (Pteromylaeus bovinus) es una especie de pez miliobatiforme de la familia Myliobatidae.[2] No se reconocen subespecies.[2]
Es de aspecto similar al águila marina (Myliobatis aquila), pero se diferencia por presentar un hocico pronunciado y puntiagudo, así como por su mayor tamaño y envergadura, la cual llega a alcanzar 1,5 m.[3] Su coloración es marrón clara en el dorso y blanco ventralmente.[4] Los ejemplares inmaduros tienen en el dorso entre siete y ocho bandas transversales que suelen desaparecer al alcanzar la edad adulta.[3] Muestra la aleta dorsal situada en el mismo nivel que las aletas pélvicas.[3]
Está ampliamente distribuido en el océano Atlántico oriental y el Índico suroccidental, así como en el mar Mediterráneo y el mar Negro.[1] La distribución exacta en el Atlántico es dudosa, aunque su presencia está confirmada fehacientemente en Marruecos, Sahara Occidental, Senegal, islas Canarias (España), Madeira (Portugal), Mauritania, Gambia, Guinea y Guinea-Bissau.[1]
Es una especie propia de aguas templadas o tropicales que habitualmente entra en estuarios y lagunas.[1]
Ocasionalmente se encuentra en pequeños grupos.[4]
Su alimentación se compone principalmente de crustáceos y moluscos del fondo marino.[4]
Es ovovivíparo.[4] La hembra pare una camada de entre tres o cuatro crías tras una gestación registrada de entre cinco y doce meses.[1]
La raya tigre o pez obispo, también llamado rata o chucho (Pteromylaeus bovinus) es una especie de pez miliobatiforme de la familia Myliobatidae. No se reconocen subespecies.
Pteromylaeus bovinus Pteromylaeus generoko animalia da. Arrainen barruko Myliobatidae familian sailkatzen da.
Pteromylaeus bovinus Pteromylaeus generoko animalia da. Arrainen barruko Myliobatidae familian sailkatzen da.
Golub ćukan (lat Pteromylaeus bovinus) riba je iz reda pravih raža (lat. Rajiformes), porodice morskih golubova (lat. Myliobatidae). Naraste do 250 cm duljine i 83 kg težine. Tijelo mu je spljošteno kao i kod svih morskih goluba, s izduljenim bočnim perajama, kao krilima koje završavaju oštro. Ima izduljenu njušku, ravnu, koja podsječa na pačji kljun, u ustima ima 7 redova ravnih zuba . Svijetlo smeđe je boje, sa desetak sivo-plavih pruga po leđima [1]. Živi na dubinama do 150 m u tropskim i toplijim morima, a hrani se pridnenim školjkašima i rakovima. Živi većino sam, a ponekad i manjim grupama. rep mu je dugačak i oblika biča. Uz sam početak repa, u kožnoj ovojnici se nalazi velika i dobro razvijena bodlja. Bodlja je od vazodentina, tvrdog, kosti sličnog materijala. Duž bodlje prostire se ventrolateralna žlijezdana udubina u kojioj se nalazi otrovno žljezdano tkivo, iz kojeg se otrov ispušta u bodlju[2]. Kako voli toplija mora, u Jadranu nije čest, najčešće se uhvati na južnom dijelu. Cijenjen je u prehrani.
Golub ćukan je riba koja prebiva po cijelom istočnom dijelu Atlantika, od Portugala do Angole, a također i oko juga Afrike, te u Indijskom oceanu oko Mozambika[3].
Golub ćukan (lat Pteromylaeus bovinus) riba je iz reda pravih raža (lat. Rajiformes), porodice morskih golubova (lat. Myliobatidae). Naraste do 250 cm duljine i 83 kg težine. Tijelo mu je spljošteno kao i kod svih morskih goluba, s izduljenim bočnim perajama, kao krilima koje završavaju oštro. Ima izduljenu njušku, ravnu, koja podsječa na pačji kljun, u ustima ima 7 redova ravnih zuba . Svijetlo smeđe je boje, sa desetak sivo-plavih pruga po leđima . Živi na dubinama do 150 m u tropskim i toplijim morima, a hrani se pridnenim školjkašima i rakovima. Živi većino sam, a ponekad i manjim grupama. rep mu je dugačak i oblika biča. Uz sam početak repa, u kožnoj ovojnici se nalazi velika i dobro razvijena bodlja. Bodlja je od vazodentina, tvrdog, kosti sličnog materijala. Duž bodlje prostire se ventrolateralna žlijezdana udubina u kojioj se nalazi otrovno žljezdano tkivo, iz kojeg se otrov ispušta u bodlju. Kako voli toplija mora, u Jadranu nije čest, najčešće se uhvati na južnom dijelu. Cijenjen je u prehrani.
La vaccarella (Pteromylaeus bovinus (Geoffroy Saint-Hilaire, 1817)), chiamata anche colombo di mare e pesce vescovo, è un pesce cartilagineo della famiglia Myliobatidae.[2]
Il suo aspetto è simile a quello dell'aquila di mare, dalla quale differisce per un muso più pronunciato e appuntito e una maggiore stazza (può raggiungere i 2,5 metri di lunghezza e gli 80 chili di peso). Il suo colore è marrone chiaro sul dorso e bianco sul ventre; gli esemplari giovani sono caratterizzate da sette o otto strisce dorsali che spariscono al raggiungimento dell'età adulta. Le sue alette dorsali sono situate alla stessa altezza di quelle pelviche.
È ampiamente presente nell'Oceano Atlantico orientale, nell'Oceano Indiano sudoccidentale, nel Mar Mediterraneo e nel Mar Nero. La sua presenza nell'Atlantico è a volte controversa anche se con tutta probabilità è confermata sulle coste del Marocco, Sahara Occidentale, Senegal, Isole Canarie, Madera, Mauritania, Gambia. Guinea e Guinea-Bissau.
È una specie propria delle acque temperate e tropicali così come di lagune ed estuari fluviali.
Vive in piccoli gruppi.
La sua alimentazione si compone soprattutto di crostacei e molluschi del fondo marino.
Si tratta di animale ovoviviparo; la femmina partorisce una figliata di tre o quattro piccoli dopo una gestazione molto variabile lunga tra i cinque ed i dodici mesi.
La vaccarella (Pteromylaeus bovinus (Geoffroy Saint-Hilaire, 1817)), chiamata anche colombo di mare e pesce vescovo, è un pesce cartilagineo della famiglia Myliobatidae.
Pteromylaeus bovinus is een vissensoort uit de familie van de adelaarsroggen (Myliobatidae).[1] De wetenschappelijke naam van de soort is voor het eerst geldig gepubliceerd in 1817 door Geoffroy Saint-Hilaire.
Bronnen, noten en/of referenties
Korocka (Pteromylaeus bovinus)[7] är en rockeart som först beskrevs av Geoffroy Saint-Hilaire 1817. Korocka ingår i släktet Pteromylaeus och familjen örnrockor.[8][9] IUCN kategoriserar arten globalt som otillräckligt studerad.[1] Inga underarter finns listade i Catalogue of Life.[8]
Denna rocka har en kroppsskiva som liknar en romb i formen med avrundade hörn. Nosen sticker ut och påminner om näbben från en anka. Kroppen har på ovansidan en ljusbrun färg och ofta finns ljusa blågråa strimmor. Undersidan är vit.[9]
Korockan använder sidolinjeorganet som känselsinne. Den har även flera ampullformiga organ som kan känna igen elektriska fält (elektroreceptorer). Dessa organ ligger huvudsakligen under nosen.[10]
Arten förekommer huvudsakligen i östra Atlanten vid Afrikas västra kustlinje från Mauretanien och Kanarieöarna i norr till Sydafrika. Utbredningsområdet kan vara delat i flera från varandra skilda populationer. Korocka finns även sydöst om Afrika norrut till Zanzibar. De flesta informationer om artens habitat och ekologi kommer från sydafrikanska studier. Enligt dessa föredrar arten kustnära havsområden som är 30 till 65 meter djupa.[1] Den besöker ofta laguner och kan leva i bräckt vatten.[1][9] Korockan lever även i Medelhavet.[9]
Individerna ligger ofta på havets botten men de gräver sig inte ner. De bildar ibland flockar med upp till 10 medlemmar. Rockan äter musslor, krabbor, bläckfiskar och andra havslevande ryggradslösa djur. Honor föder levande ungar (ovovivipari) efter 5 till 6 månader dräktighet. Allmänt föds 3 till 4 ungar per tillfälle (ibland upp till 7[9]). Den minsta ungen som iakttogs i havet hade en 35,5 cm bred kroppsskiva och en vikt av 460 g. Ungarna blir könsmogna när bålens skiva är 83 till 100 cm bred. Vid denna tidpunkt som ligger cirka 1,2 år efter födelsen väger hannar cirka 13,5 kg och dräktiga honor väger ungefär 28 kg. En vuxen individ som fångades 1967 hade en 149,5 cm bred kroppsskiva och en vikt av 56,2 kg.[1]
För några exemplar dokumenterades en ålder av 14 år.[10]
Wikimedia Commons har media som rör Korocka.
Wikispecies har information om Pteromylaeus bovinus.
Korocka (Pteromylaeus bovinus) är en rockeart som först beskrevs av Geoffroy Saint-Hilaire 1817. Korocka ingår i släktet Pteromylaeus och familjen örnrockor. IUCN kategoriserar arten globalt som otillräckligt studerad. Inga underarter finns listade i Catalogue of Life.
Подобно прочим хвостоколообразным бычьи крылатые орляки относятся к яйцеживородящим рыбам. Эмбрионы развиваются в утробе матери, питаясь желтком и гистотрофом. В помёте 3—4 новорождённых с диском шириной около 35 см[4], по другим данным 3—7 новорождённых с диском шириной 45 см[3]. В водах Сенегала беременность длится 5—6 месяцев, а у побережья ЮАР около года. Максимальная зарегистрированная ширина диска эмбриона 27 см. Самцы и самки достигают половой зрелости при ширине диска примерно 100 см, что соответствует возрасту 1,2 года. Рацион бычьих крылатых орляков состоит из крабов, креветок, брюхоногих, двустворчатых и головоногих моллюсков[4].
На бычьих крылатых орляках паразитируют моногенеи Empruthotrema chisholmae[6], Heliocotyle kartasi [7] и Myliocotyle pteromylaei[8], цестоды Caulobothrium sp.[9] и Halysioncum sp.[10], нематоды Mawsonascaris pastinacae[11] и веслоногие Pseudocharopinus pteromylaei[12].
Бычьи крылатые орляки являются объектом целевого лова в некоторых частях своего ареала. Мясо высоко ценится[3]. Вид страдает от ухудшения условий среды обитания. Данных для оценки Международным союзом охраны природы охранного статуса вида недостаточно[4]. Этих скатов иногда содержат в публичных аквариумах.
Подобно прочим хвостоколообразным бычьи крылатые орляки относятся к яйцеживородящим рыбам. Эмбрионы развиваются в утробе матери, питаясь желтком и гистотрофом. В помёте 3—4 новорождённых с диском шириной около 35 см, по другим данным 3—7 новорождённых с диском шириной 45 см. В водах Сенегала беременность длится 5—6 месяцев, а у побережья ЮАР около года. Максимальная зарегистрированная ширина диска эмбриона 27 см. Самцы и самки достигают половой зрелости при ширине диска примерно 100 см, что соответствует возрасту 1,2 года. Рацион бычьих крылатых орляков состоит из крабов, креветок, брюхоногих, двустворчатых и головоногих моллюсков.
На бычьих крылатых орляках паразитируют моногенеи Empruthotrema chisholmae, Heliocotyle kartasi и Myliocotyle pteromylaei, цестоды Caulobothrium sp. и Halysioncum sp., нематоды Mawsonascaris pastinacae и веслоногие Pseudocharopinus pteromylaei.
