Bull ray

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Bull ray
Pteromylaeus bovinus valencia.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Superorder: Batoidea
Order: Myliobatiformes
Family: Myliobatidae
Genus: Aetomylaeus
Species:
A. bovinus
Binomial name
Aetomylaeus bovinus
Synonyms

Pteromylaeus bovinusGeoffroy Saint-Hilaire, 1817 [2]

Contents

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]

Biology and ecology

The species is ovoviviparous and reach sexual maturity at four to six years old. With a low fecundity of three to four pups per litter and a long gestation of six to 12 months (depending on the geographical zone), this species has 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, and with a maximum discal width (tip to tip) of 2.22 m (7 ft 3 in), 1.5 m (4 ft 11 in) in length and weighing up to 116 kg (256 lb), [4] bull rays can be considered as giants of the shallow waters. Their maximum length and very narrow depth range of 0–30 m (0–98 ft) exposes them to various threats. Indeed, large-body, shallow-water species are at greatest risk. Bull rays appear to be extremely rare throughout the Mediterranean region, and its current population trend is highly suspected to be decreasing. Females are larger and heavier than males.

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]

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]

Threats

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 t (890 long tons; 990 short tons) 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.

Conservation and status

On a global scale, Aetomylaeus bovinus is classified as Critically Endangered. [1] 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). [1] 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.[ citation needed ]

Distribution and habitat

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.

Related Research Articles

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Manta rays are large rays belonging to the genus Mobula. The larger species, M. birostris, reaches 7 m (23 ft) in width, while the smaller, M. alfredi, reaches 5.5 m (18 ft). Both have triangular pectoral fins, horn-shaped cephalic fins and large, forward-facing mouths. They are classified among the Myliobatiformes and are placed in the family Myliobatidae. They have the largest brains and brain to body ratio of all fish, and can pass the mirror test.

<span class="mw-page-title-main">Stingray</span> Suborder of fishes

Stingrays are a group of sea rays, a type of cartilaginous fish. They are classified in the suborder Myliobatoidei of the order Myliobatiformes and consist of eight families: Hexatrygonidae, Plesiobatidae, Urolophidae (stingarees), Urotrygonidae, Dasyatidae, Potamotrygonidae, Gymnuridae and Myliobatidae . There are about 220 known stingray species organized into 29 genera.

<span class="mw-page-title-main">Eagle ray</span> Family of cartilaginous fishes

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<span class="mw-page-title-main">Trawling</span> Method of catching fish

Trawling is an industrial method of fishing that involves pulling a fishing net through the water behind one or more boats. The net used for trawling is called a trawl. This principle requires netting bags which are towed through water to catch different species of fishes or sometimes targeted species. Trawls are often called towed gear or dragged gear.

<span class="mw-page-title-main">Thorntail stingray</span> Species of cartilaginous fish

The thorntail stingray, black stingray, or longtail stingray is a species of stingray in the family Dasyatidae. It is found off southern Africa, Australia, and New Zealand from the intertidal zone to a depth of 440 m (1,440 ft). This bottom-dweller inhabits soft-bottomed habitats such as lagoons, estuaries, and reefs. Growing to 1.8 m (5.9 ft) across and over 200 kg (440 lb) in weight, the thorntail stingray is among the largest stingrays in the world. Uniformly dark above and light below, it has a diamond-shaped pectoral fin disc and a very long, whip-like tail with a fin fold underneath. The upper surface of the disc and the tail bear numerous stout, sharp thorns.

A bull ray is a species of large stingray of the family Myliobatidae.

<span class="mw-page-title-main">Round ribbontail ray</span> Species of stingray

The round ribbontail ray or blotched fantail ray, is a species of stingray in the family Dasyatidae, found throughout the nearshore waters of the tropical Indo-Pacific, as well as off islands in the eastern Pacific. It is a bottom-dwelling inhabitant of lagoons, estuaries, and reefs, generally at a depth of 20–60 m (66–197 ft). Reaching 1.8 m (5.9 ft) across, this large ray is characterized by a thick, rounded pectoral fin disc covered by small tubercles on top, and a relatively short tail bearing a deep ventral fin fold. In addition, it has a variable but distinctive light and dark mottled pattern on its upper surface, and a black tail.

<span class="mw-page-title-main">Devil fish</span> Species of cartilaginous fish

The devil fish or giant devil ray is a species of ray in the family Mobulidae. It is currently listed as endangered, mostly due to bycatch mortality in unrelated fisheries.

<i>Argyrosomus regius</i> Species of fish

Argyrosomus regius, also known as the meagre, croaker, jewfish, shade-fish, sowa, kir, corvina, salmon-bass or stone bass, is a species of fish of the family Sciaenidae. This large fish has a pearly-silver to brownish coloration and a yellow-coloured mouth. It is native to the eastern Atlantic Ocean, as well as the Mediterranean and Black Seas.

<span class="mw-page-title-main">Pelagic stingray</span> Species of cartilaginous fish

The pelagic stingray is a species of stingray in the family Dasyatidae, and the sole member of its genus. It is characterized by the wedge-like shape of its pectoral fin disc, which is much wider than long, as well as by the pointed teeth in both sexes, whip-like tail with extremely long tail spine, and uniform violet to blue-green coloration. It generally reaches 59 cm (23 in) in width. The pelagic stingray has a worldwide distribution in waters warmer than 19 °C (66 °F), and migrates seasonally to spend the summer closer to the continental shelf and at higher latitudes. The only stingray that almost exclusively inhabits the open ocean, this species is typically found in surface waters down to a depth of 100 m (330 ft). As a consequence of its midwater habits, its swimming style has evolved to feature more of a flapping motion of the pectoral fins, as opposed to the disc margin undulations used by other, bottom-dwelling stingrays.

<i>Mullus barbatus</i> Species of fish

Mullus barbatus is a species of goatfish found in the Mediterranean Sea, Sea of Marmara, the Black Sea and the eastern North Atlantic Ocean, where its range extends from Scandinavia to Senegal. They are fished, mostly by trawling, with the flesh being well regarded. The International Union for Conservation of Nature has assessed their conservation status as being of "least concern".

<span class="mw-page-title-main">Spotted eagle ray</span> Species of fish

The spotted eagle ray is a cartilaginous fish of the eagle ray family, Aetobatidae. As traditionally recognized, it is found globally in tropical regions, including the Atlantic, Pacific and Indian Oceans. Recent authorities have restricted it to the Atlantic with other populations recognized as the ocellated eagle ray and Pacific white-spotted eagle ray. Spotted eagle rays are most commonly seen alone, but occasionally swim in groups. They are ovoviviparous, the female retaining the eggs then releasing the young as miniature versions of the parent.

<span class="mw-page-title-main">Banded eagle ray</span> Species of fish

The banded eagle ray is a species of fish in the family Myliobatidae. It is found in Australia, Bangladesh, Brunei, Cambodia, China, India, Indonesia, Japan, North Korea, South Korea, Malaysia, Myanmar, Pakistan, Papua New Guinea, the Philippines, Singapore, Sri Lanka, Taiwan, Thailand, Vietnam, possibly Maldives, and possibly Mozambique. Its natural habitats are open seas, shallow seas, and coral reefs, where it is threatened by habitat loss.

<span class="mw-page-title-main">Ornate eagle ray</span> Species of cartilaginous fish

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<span class="mw-page-title-main">Common stingray</span> Species of cartilaginous fish

The common stingray is a species of stingray in the family Dasyatidae, found in the northeastern Atlantic Ocean and the Mediterranean and Black Seas. It typically inhabits sandy or muddy habitats in coastal waters shallower than 60 m (200 ft), often burying itself in sediment. Usually measuring 45 cm (18 in) across, the common stingray has a diamond-shaped pectoral fin disc slightly wider than long, and a whip-like tail with upper and lower fin folds. It can be identified by its plain coloration and mostly smooth skin, except for a row of tubercles along the midline of the back in the largest individuals.

<span class="mw-page-title-main">Coastal fish</span> Fish that inhabit the sea between the shoreline and the edge of the continental shelf

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The round fantail stingray or round stingray, is a poorly known species of stingray in the family Dasyatidae. It inhabits sandy, muddy, or rocky coastal habitats in the eastern Atlantic Ocean and the southern Mediterranean Sea. This dark-colored ray typically reaches a width of 1 m (3.3 ft), and can be identified by its nearly circular pectoral fin disk, short tail, and mostly bare skin. The round fantail stingray hunts for fishes and crustaceans on the sea floor, and exhibits an aplacental viviparous mode of reproduction. The International Union for Conservation of Nature (IUCN) does not yet have sufficient information to assess the conservation status of this species.

<span class="mw-page-title-main">Common eagle ray</span> Species of fish

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References

  1. 1 2 3 4 Jabado, R.W., Chartrain, E., Cliff, G., Derrick, D., Dia, M., Diop, M., Doherty, P., Dossa, J., Leurs, G.H.L., Metcalfe, K., Porriños, G., Seidu, I., Soares, A., Tamo, A., VanderWright, W.J. & Williams, A.B. (2021). "Aetomylaeus bovinus". IUCN Red List of Threatened Species . 2021: e.T60127A124441812. doi: 10.2305/IUCN.UK.2021-1.RLTS.T60127A124441812.en . S2CID   243549852.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  2. 1 2 White, W.T. (2014). "A revised generic arrangement for the eagle ray family Myliobatidae, with definitions for the valid genera". Zootaxa. 3860 (2): 149–166. doi:10.11646/zootaxa.3860.2.3. PMID   25283197.
  3. Barrera, Dylan; Dickerson, Caleb; Grano, Bleu; Lambert, John (2011). "Pteromylaeus Bovinus". Animal Diversity Web. University of Michigan. Retrieved 2023-02-10.
  4. 1 2 3 4 5 Froese, Rainer; Pauly, Daniel (eds.). "Aetomylaeus bovinus". FishBase . January 2016 version.
  5. 1 2 Mendez L.; Bacquet A. & F. Briand (Oct 2022). "Guide of Mediterranean Skates and Rays (Aetomylaeus bovinus)". The Mediterranean Science Commission.
  6. Schwartz, F.J. (2005). "Tail Spine Characteristics Of Stingrays (Order Myliobatiformes) Found In The Northeast Atlantic, Mediterranean, And Black Seas" (PDF). Electronic Journal of Ichthyology. 1 (1): 1-9.