Mourning Cuttlefish

Sepia plangon acquired its common name due to the appearance of the eyes, which are often surrounded by a bluish tinge.

Identification

Sepia plangon is a short armed species with a highly variable colour pattern. However it is often seen with two narrow black bands across the mantle and two large ‘eye spots’ towards the posterior end of the mantle. As mentioned, there is often a bluish tinge to the eye socket. Small papillae are also present over the body.
The cuttlebones are often found in large numbers on beaches north and south of Sydney. It is slender and elongate in shape with a deep central groove on the ventral (lower) surface and a small spine. The anterior end is acuminate while the posterior rounded.

Habitat

S. plangon is an estuarine cuttlefish often found in shallow bays and harbours at around 3-9m depth. It has been found at depths up to 83 m. Juveniles are more commonly seen in seagrass beds and adults near rocky reefs and dwarf kelp stands.

Distribution

Sepia plangon is found in the Southwestern Pacific region, in coastal waters of eastern Australia from the Gulf of Carpentaria to Sydney.

Feeding and diet

Sepia plangon is active during the day foraging for crustaceans and fishes.

Other behaviours and adaptations

The Mourning Cuttlefish is frequently found resting on the seafloor in a tripod position, using the two lower arms as stilts to raise the head. It is also capable of closely mimicking the texture of seaweed and other substrates by erecting the papillae on its body and flattening the webs on its arms. This cuttlefish is extremely fast at escape using jet propulsion, leaving behind clouds of ink.

Breeding behaviours

During courtship the females remain plain coloured, while males put on brilliant displays. Narrow, wavy, light-coloured transverse stripes appear across the upper body, and wide iridescent green bands along the base of their fins.

References

• Jereb, P., & C.F.E Roper (eds) (2005) Cephalopods of the World: Chambered Nautiluses and Sepioids, Food & Agriculture Organization of the United Nations Catalogue for Fishery Purposes, Rome, No. 4, Vol. 1
• Lu, C.C (1998) A Synopsis of Sepiidae in Australian waters (Cephalopoda: Sepiodiea). In: Voss, N.A., Vecchione, M., Toll, R.B. & Sweeney, M.J (Eds) Systematics and Biogeography of Cephalopods. Smithsonian Institution Press, Washington DC, Vol. 586, 159-190.
• 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)
• Watson-Russell, C. (1983) Cuttlefish of Sydney Harbour, Australian Natural History, 20(5): 159-164.