Common cuttlefish  (Sepia officinalis)

Common and widespread.

The cephalopods (meaning 'head-footed'), a group of molluscs containing the octopuses, squid and cuttlefish, are probably the most intelligent of all invertebrates. They have well-developed heads, with large eyes and mouths that feature beak-like jaws (3). The body of the common cuttlefish is flattened and broad, and is therefore oval in cross-section (2). A fin runs around the body from behind the head (2). Encircling the mouth there are eight 'arms' with suckers, which are used to manipulate prey, there are also two tentacles with flattened paddle-like tips, which can be rapidly extended and are used to catch prey (4). This species has excellent camouflage; it is able to change its colour to match its surroundings (2). Colour is therefore extremely variable, but is typically blackish-brown, mottled or striped, usually with paler underparts (2). Cuttlefish have an internal shell known as a cuttlebone, which is filled with gas and aids buoyancy; these shells are found washed ashore, and are often given to pet birds as a source of calcium and other minerals.

In Britain, this cuttlefish is found around southern and western coasts. Elsewhere, the species is found in the eastern Atlantic from the Baltic Sea to South Africa, and also in the Mediterranean (2).

You can view distribution information for this species at the National Biodiversity Network Gateway.

Occurs from the shallow sublittoral zone to depths of 200m, where it is found on muddy and sandy substrates (2).

Cuttlefish swim using the fin that passes around the body. They can also rapidly expel water and move quickly by 'jet-propulsion' (4). Like all cephalopods, the common cuttlefish is an active predator, feeding on molluscs, young fish, and crabs. Other species of cuttlefish may also be taken, and cannibalism has been reported (2). When threatened, this species releases ink (known as sepia) into the water to produce a protective 'cloud' which confuses predators and allows the cuttlefish to escape (4).

During spring and summer, males and females migrate to warmer water in order to spawn (2). Males often engage in spectacular displays to attract a female, in which bands of colour pass rapidly along the body; fighting over females is common (4). The eggs are attached to objects on the sea floor such as shells and seaweeds (2); after spawning, both the males and females die (4). Young cuttlefish reach maturity at 14-18 months of age, and the average life span is 1-2 years (2).

This common species is fished commercially, and is also caught in bycatch (2).

No conservation action has been targeted at this common species.

There may be further information about this species available via the National Biodiversity Network Gateway.

View information on this species at the UNEP World Conservation Monitoring Centre.

For more on this species see the Marine Life Information Network species account, available from:
http://www.marlin.ac.uk/species/Sepiaofficinalis.htm