The eagle ray is easily identified by its triangular wing flaps, rounded head protruding from the main body and its long whip-like tail. The tail has a small dorsal fin at the base, followed by a venomous spine. They are olive-green in colour and have an array of bluish bars, spots and crescents over the upper surface of the body. They are benthic feeders, blowing a jet of water over sediments on the seafloor to expose their prey. Crabs and molluscs are then ground in the mouth of the eagle ray which contains a series of crushing plates. Eagle rays are extremely fast swimmers, and attain their name “eagle” ray due to their ability to leap high out of the water. The female eagle rays are viviparous, giving birth to 3 to 7 live young. They grow to a large size of 2.41 metres.
The eagle ray is the only species in the family Myliobatidae to exist in southern Australian waters, where they range from Jurien Bay, WA to Moreton Bay, Qld. They are common in very shallow to deep offshore waters to depths of 85 metres.
Other common names include: Southern Eagle Ray
Occurrence at the Busselton Jetty:
Eagle rays are often seen gliding over the substrate in the clear shallow waters either side of the Busselton Jetty. From the windows of the underwater observatory they are not so common. They have been sighted from the seagrass window which gazes out over a sandy, sparsely covered seagrass bed, the rays ideal habitat. Unfortunately many we do see, lack their long tail, and hence their spine, which is the eagle rays main defensive strategy against predators.
Image by: Busselton Jetty Inc.