Sepia officinalis

Sepia officinalis is generally found in the eastern North Atlantic, throughout the English Channel, and south into the Mediterranean Sea so it is often referred to as the "European Cuttlefish". However, populations have also been recorded along the west coast of Africa, and as far south as South Africa. (Jereb and Roper, 2005; King, 2009)

Sepia officinalis is a marine organism, categorized as a “shallow water cephalopod”, dwelling in sandy or muddy substrates. Its habitat ranges from subtidal waters to depths of 200 meters. Members of this species follow seasonal migrations. They spend spring and summer in inshore waters, then migrate to depths of 100 m to 200 m during autumn and winter. Sepia officinalis commonly spends the daytime hidden in sand. (Jereb and Roper, 2005; King, 2009; Neves, et al., 2009)

Sepia officinalis measures up to 45 cm in mantle length, ranging from 30 cm in subtropic areas to 49 cm in temperate areas. Weights are between 2 kg (subtropic areas) and 4 kg (temperate areas). The largest recorded individual reached a mantle length of 60 cm. European cuttlefish have large eyes and a mouth with beak like jaws located at the base of the mantle. The mantle houses reproductive and digestive organs, as well an internal shell called the cuttlebone. The cuttlebone shape is oblong with a rounded posterior end and an anterior end that tapers to a point.

The body of S. officianalis is broad and dorso-ventrally flattened, having an oval shaped cross section. A pair of flat, wide fins runs the length of the mantle. The mouth is surrounded by eight arms and two longer tentacles, all equipped with suckers. Mature Sepia officinalis exhibit a zebra stripe pattern on the dorsal surface of their mantles during breeding season. Adult males are distinguished by white and black zebra bands on their fourth arm, as well as white arm spots. Sepia officinalis is able to change the color and even texture of its skin using structures called chromatophores, leucophores, and iridophores. These structures function to camouflage this species to its variable surroundings. Generally, however, Sepia officinalis has a mottled black or brown color. (Jereb and Roper, 2005; "Cuttlefish, Sepia officinalis at Marine Bio", 2010; "Common cuttlefish- Sepia officinalis", 2003)

Females deposit clusters of eggs on seaweed, shells, and other substrate along the seafloor. Eggs measure 6 to 9 mm in diameter, hatching after about 2 months, or 30-90 days, depending on water temperature. Once hatched, the young Sepia officinalis have a total length of 50 mm. Newly hatched young are well developed and can almost immediately start feeding on small prey. Growth rates vary with temperature, the young growing faster at lower temperatures. Sepia officinalis generally reaches maturity at 14 to 18 months of age. (Jereb and Roper, 2005; King, 2009; "Common cuttlefish- Sepia officinalis", 2003)

Sepia officinalis has separate male and female sexes. In the spring and summer, male and females migrate to shallow, warmer waters to spawn. They exhibit elaborate courtships, wherein males attract females through spectacular displays of colored bands passing rapidly along their bodies. Males then hold their arms stiffly in a basket formation to show their virility. Similarly, females display a uniform gray color when ready to mate. Mate guarding, in which males aggressively fight over and guard their females, is also common. (Hart, 2010; Jereb and Roper, 2005; King, 2009; Neves, et al., 2009)

Mating in Sepia officinalis involves internal fertilization. The male deposits spermaphores into the female’s buccal membrane using a hectocotylized arm (tentacle arm used as intromittent organ). Males carry as many as 1400 spermatophores, while females carry somewhere between 150 and 4000 eggs, depending on body size. Sepia officinalis reaches sexual maturity at 14 to 18 months of age. Females can lay eggs several times at the ends of their lives. However, after spawning both male and females die. (Jereb and Roper, 2005; King, 2009; "Cuttlefish, Sepia officinalis at Marine Bio", 2010; "Common cuttlefish- Sepia officinalis", 2003)

Fertilized eggs are stored in the oviduct of the female Sepia officinalis until they are ready to be deposited. Eggs are produced with deposits of ink, to color and, therefore, camouflage the eggs for protection. A young Sepia officinalis hatches with a yolk to provide nutritious support until they are able to catch their own prey. ("Cuttlefish, Sepia officinalis at Marine Bio", 2010)

Sepia officinalis has a typical lifespan of one to two years. (King, 2009)

Sepia officinalis is active at night and spends most of its time on the sea floor. It swims mainly to eat, mate or fight with other cuttlefish. The undulating fins on either side of its mantle aid in swimming. The European cuttlefish also has the ability to rapidly propel itself by forcing water through its siphon. Sepia officinalis is typically a solitary species except during mating. Cuttlefish can change the color and texture of its skin within seconds, allowing it to camouflage with its environment and to communicate with other cuttlefish or predators. Special structures within its skin enable it to change colors quickly. The cuttlefish expands and contracts these structures to create the different patterns of colors and textures on its skin. Sepia officinalis can create uniform body patterns or to exhibit multiple patterns at the same time. Another anti-predatory behavior is to secrete ink. (Dunlop, 2003; Hart, 2010; "Cuttlefish, Sepia officinalis at Marine Bio", 2010)

The home range for Sepia officinalis varies from 90 to 550 meters. This means that the typical area a cuttlefish will roam in is between 5,300 square meters and 23,700 square meters. (Aitken, et al., 2005)

Sepia officinalis has highly developed eyes and often communicates with other cuttlefish and predators using visual cues. Not only does it use its skin-changing ability to convey messages, but it also communicates by swimming in certain patterns or holding its tentacles in certain postures. In addition to communicating by altering its skin’s appearance, a cuttlefish can also indicate that it feels threatened by ejecting black ink from its siphon. (Dunlop, 2003; Hart, 2010)

Sepia officinalis preys upon a wide variety of animals. It primarily feeds on crustaceans and fish, but has also been known to eat gastropods, nemertean worms, polychaetes and even other cuttlefish. Sepia officinalis is an ambush predator that hunts by blending in with its background and sneaking up on prey. When the prey is close, Sepia officinalis has two modes of attack. One is to shoot out its two longer tentacles, grab the prey using the suckers on the tentacular clubs at the tips of the tentacles and bring the prey into its beak to feed. The other attack mode is pounce on its prey and use its arms to capture and maneuver the prey while it tears at the prey with its radula and beak. Both adult and immature cuttlefish hunt for food during the night. Some studies have shown that cuttlefish embryos have the ability to learn about prey items while still encased in their eggs using their fully-developed eyes to observe prey species. Hatchlings that observed crabs while inside their eggs preferred to eat crab over other prey items. (Boletzky and Hanlon, 1983; Dunlop, 2003; Mangold and Young, 1996; Walker, 2008)

Sepia officinalis is prey for large fish, seals, sharks, dolphins and whales. The cuttlefish avoids predation by camouflaging with its environment, disorienting predators by releasing ink when threatened, and propelling itself away from danger. (Dunlop, 2003; "Cuttlefish, Sepia officinalis at Marine Bio", 2010)

Sepia officinalis is highly active, grows quickly and expends high amounts of energy per reproductive effort. In order to meet its energetic needs, a cuttlefish will eat voraciously. Therefore, cuttlefish play an important ecological role as consumers. Because they eat a wide variety of prey and can be highly mobile, cuttlefish can fill a broad and flexible ecological niche. (Aitken, et al., 2005; Mangold and Young, 1996; Wood, 2009)

Sepia officinalis is commercially fished and eaten by humans. Its ink has many uses including homeopathic medicinal uses and use as dyes and paint. Many people keep cuttlefish as pets. People often give cuttlebones from cuttlefish to their pet birds as dietary supplements and to keep their birds' beaks in good health. (Davis, 2010; Dunlop, 2003; Unknown, 2007; Wood, 2009)

There are no known adverse effects of Sepia officinalis on humans.

This species of cuttlefish are believed to be abundant and faces no threat of extinction. Studies indicate that fishing is occurring around the maximum sustainable yield, so no special conservation status is applied to them. (Royer, et al., 2006)