Species: Mobula alfredi
Bundjalung name: Unknown
Status (IUCN): Vulnerable to extinction

Characteristics

• Length/size: With a wingspan (disc width) of up to 5 metres, they’re one of the largest rays in the world. They can weigh up to 700 kg.

• Colour: Usually grey/black on their back with lighter grey/white patches, and white on the belly often with grey/black spots. These dark spots can be used to identify individual manta rays, like a fingerprint. Some rays are melanistic (mostly black) and occasionally leucistic (mostly white) and there’s even one record of a pink manta!

• Breeding/reproduction: All mobulid rays reproduce via aplacental viviparity, meaning they give birth to live young that are hatched from an egg inside the female’s uterus. The pup, which is wrapped in a thin membranous egg case, hatches inside the mother’s oviduct and then feeds on the mother’s uterine milk until it is fully developed and ready to be born. Gestation is estimated to be 12 or 13 months and pups are around 1.2 – 1.5 metres wide when born. The young come out with their wings wrapped around them like a burrito. 

• Diet: They are observed filter-feeding on zooplankton (copepods, shrimp, crab larvae) in surface waters, but it is believed they gain much of their energetic requirements when foraging on zooplankton at depth. The cephalic lobes (or ‘head fins’ located either side of their mouth) can be rolled up for streamlined travel, then unfurled to form a funnel-like shape around their mouth when feeding. 

Habitat: Preferring warmer waters, these rays are found throughout the tropical Indo-Pacific, mainly in coastal waters. 

Threats: Overfishing is the biggest threat, as slow reproducers it’s easy for local populations to become depleted. There are targeted fisheries in many countries for their meat and products such as the gill plates (used in Traditional Chinese Medicine). Locally, entanglement is an issue (such as in shark nets or fishing waste). Climate change and microplastics (which can be filtered along with their food) are also likely to have negative impacts. 

Local research: These charismatic rays visit the Byron Bay Hope Spot in the warmer months (between September and May) when they’re often spotted attending cleaning stations at Nguthungulli / Julian Rocks. Over 150 individuals have been identified off Byron Bay by Project Manta using photo-ID, and there have been approximately 300 confirmed sightings of these individuals within the Cape Byron Marine Park. Some of the identified manta rays have been recorded moving north to the Great Barrier Reef, and south to the Solitary Island Marine park, demonstrating that they are part of a much bigger population along Australia’s east coast.