Focusing on the Family: Sepiidae - Cuttlefish
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Sepiidae - Cuttlefish
The Cephalopod meaning “head foot” belonging to the phylum Mollusc is characterized by a prominent head and modified mollusc foot in the form of arms or tentacles. The class contains two sub classes, Coleoidea in which species have either no shell or an internal shell; this class includes octopus, squid and cuttlefish. The second class is Nautiloidea where the shell is still in place, Nautilus are grouped here.
Cuttlefish Eye is 'W' shaped.
They appeared on earth approximately 500 million years ago and today live in all oceans of the world at all depths. There are approximately 800 living species of Cephalopod and surprisingly little is known about the majority of this species, most do not inhabit coral reefs but live in the deep sea and it would seem none live in fresh water.
The Hyponome - muscular funnel..
They are extremely intelligent and have superb eyesight. Cryptic behavior is their main defense as few are poisonous. Their soft bodies are unprotected by armor, possessing no tough scales or defensive spines. Some have been known to mimic other poisonous creatures but mostly they blend perfectly into their surroundings, their camouflage is so efficient they have been known to fool each other. Some possess an ink sac for defense, which confuses their predator or prey. These carnivores eat fish, worms, crustaceans, and other molluscs.
The Flamboyant Cuttlefish walking
along the Seabed.
They communicate via their skin using cells containing more than one pigment called chromatophores.
The main method of movement is jet propulsion; this is achieved by taking in water to the gills then with the contraction of the muscles force water through the hyponome, a muscular funnel or siphon, illustrated above. Using this method they would usually move backwards but by aiming the hyponome in different directions they control their direction of travel. Sometimes octopuses will favor walking along the seabed.
Cuttlefish and squid can also maneuver in any direction with the aid of a skirt of muscle that ripples around their mantle, this technique is slower than the jet method. Many cephalopods have short life spans and reproduce only once. If you can win the trust of a Cephalopod you can have hours of fun playing and stroking them but you must be patient and kind.
Family: Sepiidae - Cuttlefish
Cuttlefish Mating.
Cuttlefish have an internal shell known as a cuttle bone, this bone is often seen washed up on beaches, they are also collected and given to birds as a good source of calcium and
keep their beaks in trim.
A Cuttlefish Feeding
The bone is used to control buoyancy by adding or reducing the liquid to gas ratio and this bone feature sets them apart from the squid, who have no cuttlebone.
They have highly developed big eyes similar to humans but the pupil is “W” shaped. They are thought to live up to two years of age.
Mating occurs face to face, the male using a long modified arm called a hectocotylus and placing sperm in a pouch below the females mouth, illustrated in image three. Once fertilized the female will lay many eggs and probably die afterwards. Their predators are shark, larger fish,other cuttlefish and of course man.
To feed they quickly shoot out a long modified tentacle with suckers on the end which grasps their prey. The image below illustrates the feeding tentacle and circled in yellow is the fish which is about to be food.
Long Modified Tentacle about to grasp a small fish.
Flamboyant Cuttlefish - Metasepia pfefferi
Amazing ability of The Flamboyant
Cuttlefish to change coloration.
This species is well worth highlighting for its beauty and rarity. They are highly prized on a divers “must see” list. Distribution, central indo region, southern Philippines to Northern Australia.
Imperial Partner Shrimp
living on the body of a
Flamboyant Cuttlefish.
Once discovered, instead of leaving the area they will usually stay in the same place for some months so revisiting is possible. Rather than seeing this species swimming they prefer to walk the substrate on two front tentacles and two skin flaps located on the underbelly, this is clearly illustrated within our field guide images. Look for the sandy appearance on the "walking" front tentacles and the underbelly skin flaps, this is where the creature makes contact with the substrate.
They are active in daylight hours and their coloration is generally brown to match the substrate (darker in Indonesia due to darker sand).
Colorful Flamboyant displaying pulsating chevrons
along its body.
They show flamboyant displays of red, yellow, white and pink chevrons that move up and down their bodies pulsating in a mesmerizing rhythm. Like other cuttlefish they produce instant colour changes.
Their elaborate coloration may indicate a poisonous bite like its cousin the Blue Ringed Octopus.
Their maximum size is approx. 10cm.
Imperial Partner Shrimps live a symbiotic relationship with many creatures including cuttlefish for more information please visit our Marine Biology Crustacean page.
Again mostly active at night, this small species grows to a maximum of 5cm. Its cryptic behavior is particularly effective making them very hard to find.
One of the largest cuttlefish, up to 50cm in length and found in waters from the Red Sea through to the entire Indo Pacific.
In its undisturbed state this species is quite easily identified by the lines on the body. However if it feels threatened and displays texture and colour changes it may be easily confused with the Broadclub as they are both fairly large cuttlefish. This species can exceed 40cm in size and is found from the Red Sea to Indo Pacific.
Found on the Eastern Coast of Australia this species reaches up to 15cm in length. In the central Indonesian region a sub species of this appears to exist. They share behavioral and physical similarities. However the Semporna species is generally much smaller than the one found in Australia. We have observed and photographed this possible subspecies year round and have never found one to be larger than 5cm.
Found Tropical Western Pacific from the Philippines/ Indonesia across northern Australia (WA, NT, QLD, NSW).
This species is mainly active at night but can be observed during daylight hours. Generally living in sand and silt habitats from shallow water to 180m. The maximum size being up to 10cm.
Without dissecting the cuttlebone correct identification of many sepia is very difficult, especially for the smaller species. Their ability to change skin texture and coloration to suit habitat and communicate makes describing some of these creatures provisional.
