White-striped Octopus

This species has one of the widest distributions of all octopus, maintained by the planktonic life stage of the hatchlings.

Identification

The upper arms of Callistoctopus ornatus are much longer and thicker than the other arms. They are pink to red in colour with paired white spots down arms and short longitudinal white stripes on their mantle. This species can weigh several kilograms, and can reach an armspan of up to 2m.

Habitat

C. ornatus are primarily found on coral reefs. Lairs identified on the southern Great Barrier Reef consist of deep vertical holes excavated in coral rubble, in which entrances are sealed during the day with rubble.

Distribution

The White-Striped Octopus is found throughout tropical waters in the Indo-Pacific, from Hawaii and Easter Island to Durban in South Africa. In Australian waters it is found from northern New South Wales around the northern coastline to Perth in Western Australia.

The distribution of C. ornatus appears to be limited to tropical waters within the 20°C isotherm. However specimens collected in the warm temperate waters of New South Wales are probably a result of common incursions by the planktonic juveniles carried south in the warm-water eddies of the East Australian Current.

Feeding and diet

The species appears to have a diverse diet including fish, crustaceans and other octopuses. The stomach contents of these octopuses regularly contain the beaks of other octopus species. Active at night, C. ornatus can be observed foraging over reef flats or on sand and gravel substrate during night low tides.

Breeding behaviours

Females lay up to 35 000 small eggs, each about 2mm long. The tiny hatchlings enter the plankton and are carried in surface currents over deep waters between their coral reef habitats.

References

• Norman, M., (2000) Cephalopods- A World Guide, ConchBooks, Germany (Hackenheim)
• Norman, M & A. Reid., (2000) A Guide to Squid, Cuttlefish and Octopuses of Australasia, CSIRO Publishing, Victoria (Collingwood)
• Norman, M.D, (1993) Octopus ornatus Gould, 1852 in Australian waters: Morphology, distribution and life history, Proceedings of the Biological Society of Washington, 106(4): 645-660.