Bull ray

For other species of the same name, see Bull ray (disambiguation).

Bull ray
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Subclass: Elasmobranchii
Order: Myliobatiformes
Family: Myliobatidae
Genus: Aetomylaeus
Species:
A. bovinus
Binomial name
Aetomylaeus bovinus
Synonyms

Pteromylaeus bovinus Geoffroy Saint-Hilaire, 1817[2]

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[4]. With a low fecundity of three to four pups per litter [5] 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),[6] bull rays can be considered as giants of the shallow waters. Like in many elasmobranch species, females are larger and heavier than males. The species does exhibit some schooling behaviours, that are currently not understood. [7]

Their large maximum size and general preference for shallow depth ranges of 0–30 m (0–98 ft) exposes them to various threats. Bull rays appear to be extremely rare throughout the Mediterranean region, and its current population trend is decreasing, with an estimated population decline of >80% in the last 3 generations. [8]

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.[6]

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 [9]. They often cause damage to clam and oyster farms.[10]

The dorsal patterns of bull rays are consistent as they age, allowing for photo identification methodologies to identify specific individuals. [11] Similar methodologies are well documented and utilised for other elasmobranch species with unique patterns such as the Whale shark and Manta ray. [12][13][14]

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 [15].

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][16]

Distribution and habitat

The full distribution of the bull ray is uncertain but it is known to be found in the Mediterranean Sea,[10] 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.[6][17]

It is found between the surf zone and depths of 65 m (213 ft) or more and also enters estuaries and lagoons.[6] Some of these shallow coastal habitats may function as nursery areas, such as in Malta. [18]

The species frequents both the bottom and the surface and sometimes leaps from the water.[6]

Various aspects of the ecology and distribution of the species remain unknown, such as population size, trends, and movement dynamics. However, like many members of the family Myliobatidae, Aetomylaeus bovinus is a migratory species, with some tagged specimens off South Africa demonstrating migrations in excess of 900km, and seasonal Philopatry. [19][20][21]

References

  1. ^ a b c d 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. ^ a b 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. Bibcode:2014Zoot.38600.2.3W. 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. ^ BAŞUSTA, Nuri; ASLAN, Ergün (2018). "Age and growth of bull ray Aetomylaeus bovinus (Chondrichthyes: Myliobatidae) from the northeastern Mediterranean coast of Turkey". doi:10.21411/CBM.A.5F77152E. ISSN 2262-3094. {{cite journal}}: Cite journal requires |journal= (help)
  5. ^ Seck, Amadou Abdoulaye; Diatta, Youssouph; Gueye-Ndiaye, Absa; Capapé, Christian (2002-06-15). "Observations on the reproductive biology of the Bull ray, Pteromylaeus bovinus (E. GEOFFROY SAINT-HILAIRE, 1817) (Chondrichthyes: Myliobatidae) from the coast of Senegal (Eastern tropical Atlantic)". Acta Adriatica. 43 (1): 87–96. ISSN 1846-0453.
  6. ^ a b c d e Dulčić, Jakov; Lipej, Lovrenc; Orlando-Bonaca, Martina; Jenko, Rados; Grbec, Branka; Guélorget, Olivier; Capapé, Christian (2008), The bull ray, Pteromylaeus bovinus (Myliobatidae), in the northern Adriatic Sea, Société Française d'Ichtyologie, doi:10.26028/CYBIUM/2008-322-004, retrieved 2026-01-20
  7. ^ Akyol, Okan; şEn, Halil; Capapé, Christian (2022-12-29). "Occurrence of a Shoal of Bull Ray Aetomylaeus bovinus (Myliobatidae) Around a Sea-Cage Farm in İskenderun Bay (Türkiye, NE Mediterranean Sea)". Çanakkale Onsekiz Mart University Journal of Marine Sciences and Fisheries. 5 (2): 199–202. doi:10.46384/jmsf.1185563. ISSN 2651-5326.
  8. ^ IUCN (2020-08-04). Aetomylaeus bovinus: 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.: The IUCN Red List of Threatened Species 2021: e.T60127A124441812 (Report). International Union for Conservation of Nature. doi:10.2305/IUCN.UK.2021-1.RLTS.T60127A124441812.en.
  9. ^ Mulas, Antonello; Bellodi, Andrea; Carbonara, Pierluigi; Cau, Alessandro; Marongiu, Martina Francesca; Pesci, Paola; Porcu, Cristina; Follesa, Maria Cristina (2021-08-25). "Bio-Ecological Features Update on Eleven Rare Cartilaginous Fish in the Central-Western Mediterranean Sea as a Contribution for Their Conservation". Life. 11 (9): 871. Bibcode:2021Life...11..871M. doi:10.3390/life11090871. ISSN 2075-1729. PMC 8471685. PMID 34575020.
  10. ^ a b Mendez L.; Bacquet A. & F. Briand (Oct 2022). "Guide of Mediterranean Skates and Rays (Aetomylaeus bovinus)". The Mediterranean Science Commission.
  11. ^ Matthews, Charlie; Caruso, Christian; Kell, Charlotte; Babbs, Sophie; Parreira do Amaral, Thaís; Ducker, Beth; Nowell, Greg; Solleliet-Ferreira, Silvio (2025-09-23). ""Nursery bays and hidden rays": First insights into long-term monitoring of Bull Rays (Aetomylaeus bovinus) within the Maltese Archipelago". Frontiers in Marine Science. 12 1653284. Bibcode:2025FrMaS..1253284M. doi:10.3389/fmars.2025.1653284. ISSN 2296-7745.
  12. ^ Moskvyak, Olga; Maire, Frederic; Armstrong, Asia O.; Dayoub, Feras; Baktashmotlagh, Mahsa (2019), Robust Re-identification of Manta Rays from Natural Markings by Learning Pose Invariant Embeddings, arXiv:1902.10847, retrieved 2026-01-20
  13. ^ Town, Christopher; Marshall, Andrea; Sethasathien, Nutthaporn (July 2013). "M anta M atcher: automated photographic identification of manta rays using keypoint features". Ecology and Evolution. 3 (7): 1902–1914. Bibcode:2013EcoEv...3.1902T. doi:10.1002/ece3.587. ISSN 2045-7758. PMC 3728933. PMID 23919138.
  14. ^ Arzoumanian, Z.; Holmberg, J.; Norman, B. (December 2005). "An astronomical pattern-matching algorithm for computer-aided identification of whale sharks Rhincodon typus". Journal of Applied Ecology. 42 (6): 999–1011. Bibcode:2005JApEc..42..999A. doi:10.1111/j.1365-2664.2005.01117.x. ISSN 0021-8901.
  15. ^ Matthews, Charlie; Caruso, Christian; Kell, Charlotte; Babbs, Sophie; Parreira do Amaral, Thaís; Ducker, Beth; Nowell, Greg; Solleliet-Ferreira, Silvio (2025-09-23). ""Nursery bays and hidden rays": First insights into long-term monitoring of Bull Rays (Aetomylaeus bovinus) within the Maltese Archipelago". Frontiers in Marine Science. 12 1653284. Bibcode:2025FrMaS..1253284M. doi:10.3389/fmars.2025.1653284. ISSN 2296-7745.
  16. ^ Matthews, Charlie; Caruso, Christian; Kell, Charlotte; Babbs, Sophie; Parreira do Amaral, Thaís; Ducker, Beth; Nowell, Greg; Solleliet-Ferreira, Silvio (2025-09-23). ""Nursery bays and hidden rays": First insights into long-term monitoring of Bull Rays (Aetomylaeus bovinus) within the Maltese Archipelago". Frontiers in Marine Science. 12 1653284. Bibcode:2025FrMaS..1253284M. doi:10.3389/fmars.2025.1653284. ISSN 2296-7745.
  17. ^ 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.
  18. ^ Matthews, Charlie; Caruso, Christian; Kell, Charlotte; Babbs, Sophie; Parreira do Amaral, Thaís; Ducker, Beth; Nowell, Greg; Solleliet-Ferreira, Silvio (2025-09-23). ""Nursery bays and hidden rays": First insights into long-term monitoring of Bull Rays (Aetomylaeus bovinus) within the Maltese Archipelago". Frontiers in Marine Science. 12 1653284. Bibcode:2025FrMaS..1253284M. doi:10.3389/fmars.2025.1653284. ISSN 2296-7745.
  19. ^ Elston, C; Murray, Ts (2024-04-02). "Multi-method approach identifies a South African estuary as an important elasmobranch habitat and potential nursery ground". African Journal of Marine Science. 46 (2): 91–102. Bibcode:2024AfJMS..46...91E. doi:10.2989/1814232X.2024.2326814. ISSN 1814-232X.
  20. ^ Elston, Chantel; Murray, Taryn S.; Parkinson, Matthew C.; Filmalter, John D.; Cowley, Paul D. (November 2023). "Female Diamond Rays Gymnura natalensis and Bull Rays Aetomylaeus bovinus Display Seasonal Philopatry to South African Estuaries". Estuaries and Coasts. 46 (7): 1880–1894. Bibcode:2023EstCo..46.1880E. doi:10.1007/s12237-023-01239-1. ISSN 1559-2723.
  21. ^ Elston, Chantel; Murray, Taryn S.; Rogers, Toby; Parkinson, Matthew C.; Mann, Bruce Q.; Daly, Ryan; Filmalter, John D.; Cowley, Paul D. (May 2025). "Diamond Gymnura natalensis and duckbill Aetomylaeus bovinus rays undertake nationwide coastal migrations". Journal of Fish Biology. 106 (5): 1344–1359. Bibcode:2025JFBio.106.1344E. doi:10.1111/jfb.15728. ISSN 0022-1112.
allikas: http://en.wikipedia.org/wiki/Pteromylaeus_bovinus