Aetomylaeus bovinus

The bull ray, scientifically identified as Aetomylaeus bovinus and also commonly known as the duckbill ray or duckbill eagle ray, is a large species of stingray found in coastal waters off Europe and Africa. Its distinctive bull-like head shape and its long, flat, round snout, which earns it the "duckbill" moniker, are key physical characteristics. This ovoviviparous species is a significant component of coastal marine megafauna, capable of reaching impressive sizes with a maximum discal width of 2.22 meters and a weight of up to 116 kg.

Biology and Ecology

Bull rays exhibit a sensitive life history, characterized by ovoviviparous reproduction, sexual maturity reached between four to six years of age, a low fecundity of three to four pups per litter, and a gestation period of six to twelve months. They are considered "bentho-pelagic" feeders, meaning they forage for their diet of invertebrates, including crabs, squids, and molluscs, on the sea floor and in the water column. While much about their ecology and behavior remains to be understood, they have been observed to engage in schooling behaviors. Females of the species are typically larger and heavier than males. Unique dorsal patterns on bull rays allow for individual identification through photo-identification methodologies.

Distribution and Habitat

The distribution of the bull ray is extensive, encompassing the Mediterranean Sea, the Black Sea, and the eastern Atlantic Ocean from Portugal down to Guinea. It is also found along the coasts of South Africa, extending into the Indian Ocean up to Maputo Bay in southern Mozambique, and has been recorded as far north as Zanzibar and Kenya. They inhabit shallow coastal zones, typically found between the surf zone and depths of approximately 65 meters, and also venture into estuaries and lagoons, some of which may serve as critical nursery areas.

Conservation Status and Threats

Globally, Aetomylaeus bovinus is classified as Critically Endangered, with a particularly alarming status in the Mediterranean Sea where it is among the 53% of native elasmobranchs at risk of extinction. Population trends indicate a significant decline, estimated at over 80% in the last three generations or 45 years, according to IUCN assessments. The species faces numerous threats, predominantly from fisheries, where it is frequently caught as by-catch in pelagic trawling, bottom trawling, trammel nets, gill nets, and spearfishing. Habitat degradation also poses a considerable risk. Despite its endangered status, there are currently no species-specific conservation measures in place, highlighting a critical need for further research into its population dynamics, habitats, ecology, and threats to inform effective protective strategies. This includes the protection of its habitats, monitoring and management of its harvest, and the implementation of educational and awareness programs.