Summary
Haliotis ovina shells showing dorsal spiral spire and internal nacreous
surface (left) (Photo from Wikimedia Commons)
Raised and open holes (tremata) are visible on the
dorsal view of the shell (right) (Author's photo)
Abalone are marine gastropod molluscs which can be found throughout the world in tropical and temperate waters. They inhabit shallow waters less than 30 m deep and are found on reefs and rocky shorelines (Geiger and Poppe, 2000; Degnan et al. 2006). Many people are likely to be familiar with the larger temperate abalone species that are farmed and fished commercially in the waters of southern Australia, like the greenlip (Haliotis laevigata) and the blacklip (Haliotis rubra) abalone (Jarayabhand and Paphavasit, 1996; PIRSA Fisheries and Aquaculture, 2012).
There are three species of abalone found on the Great Barrier Reef; Haliotis ovina (Sheep's Ear Abalone), Haliotis asinina (Ass's Ear Abalone) and Haliotis varia (Variable Abalone or Common Ear Shell) (Degnan et al., 2006), but these species are also found throughout the Indo-Pacific, as far north as southwestern Japan (Geiger and Poppe, 2000).
They are usually distinguished by their shell features such as overall size, shape, colour and patterning, as well as the colour and mass of their muscular foot. All three tropical abalone species are herbivores, feeding on the abundant macroalgae found on the reef.
H. ovina is a nocturnal feeder, hiding in crevices and between dead coral during the day. It inhabits the intertidal zone near the reef crest and has been found at depths of up to 30 metres (Geiger and Poppe, 2000). |