Common Name: Reef Manta Ray
Scientific Name: Manta Alfredi
Why are they vulnerable?
The primary threat is fishing in any form. The fishing industry is the basis of many human populations, and fish is a widely eaten food around the world. So, many oceans are filled with nets waiting for species to come inside to be captured. Sometimes reef manta rays also come without fishermen intending to catch them. Once inside the net, manta rays can injure or suffocate because it becomes difficult for them to obtain oxygen from the water.
Manta alfredi are a more localized species, residing within smaller geographical areas, they are still capable of long-range movements .The species is found in the Indian, Pacific and Atlantic oceans in tropical and subtropical waters. However, their distribution is not uniform and it is itself fragmented.
Acoustic telemetry is currently being employed to examine habitat use of Manta alfredi in southern Mozambique. They are looking at the rate of movement, broad-scale movements and seasonal shifts in habitat selection. Individual reef mantas are being tagged regularly with acoustic tags, which have a detection range by the receivers of approximately 500 meters
CURRENT POPULATION: about 100–2,000 individuals
Populations are STABLE in locations where the Reef Manta Ray can receive some level of protection, such as Australia, Hawaii, Japan, the Maldives and Yap, but are in DECLINE in areas where they are fished, or are under threat from anthropogenic influences. This includes places such as Indonesia, Thailand and Mozambique where encounter rates have dropped significantly over the last five years or anthropogenic mortality has been elevated.
There have been a greater number of sightings in the Indian Ocean, especially from the Red Sea to South Africa in the west of the ocean and from Thailand to western Australia in the eastern Indian Ocean. In Pacific waters, The sightings in the Atlantic Ocean have actually been very few and even less than the North.
Their habitats are often found near the coast and are found mainly near coral and rocky reefs and around atolls, bays, groups of islands and seamounts.
Almost all rays feed on prey living close to, on, or just underneath the bottom. They are often called the vacuum cleaners of the ocean. They have this nickname because the animals that feed on them live on the bottom as well. Rays feed mainly on invertebrates and small vertebrates, with prey ranging from quite large fish down to tiny crustaceans. All known rays are carnivorous and very high on the food chain.
Since they are so high up on the food chain, they are very influential in the chain. If they weren't alive, many of the species lower on the food chain would begin to overpopulate and cause other problems in the ocean.
Vulnerability in the Water (Threats and Conservation)
Their natural predators are large sharks, killer whales (Orcinus orca) and false killer whales. If attacked and wounded, their tissues regenerate quickly.
Aside from animals, Fishing in any of its forms is the greatest threat to their survival. Humans hunt manta rays to use their flesh as food. They also commonly use their liver to obtain it's oil and use it in local medicinal remedies. Their gill rakers and skin are also present in the market, and they are usually caught to be kept in captivity.