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By Robin J. Case
Geographic Range
This species has a world-wide distribution. It is abundant in the Mediterranean Sea, the Eastern Atlantic Ocean, and in Japanese waters.
Biogeographic Regions:
indian ocean (native 
); atlantic ocean (native ); pacific ocean (native ).
Habitat
Octopus vulgaris is found in tropical, subtropical, and temperate waters between the surface and a depth of 100 to 150 meters. . It is not found in polar or subpolar regions. It lives in costal waters and the upper part of the continental shelf.
Physical Description
Reach 1-3 feet in length including arms. The skin is smooth. Like other octopuses, members of this species have 8 arms that are lined with suckers, and they lack any internal shell.
Development
The duration of embryonic development is related to temperature, as it is in all cephalopods, and it also depends on the size of the egg.
Reproduction
Octopus vulgaris has individuals of both sexes. During mating, the male approaches the female, who fends him off for a while, but then accepts him. He sits next to her or mounts her, inserting the hectocotylus in her mantle cavity to pass the spermatophores. They may copulate for several hours. The same pair often repeat mating over a period of a week or so, but a male copulates with other females and a female accepts other males. Mating often occurs when the females are immature. Only females ready to lay eggs consistently fend off the males.
Mating systems:
polygynandrous (promiscuous) .
Females become restless and search for a sheltered place where they can lay and brood the eggs without disturbance. The spermatophores are placed in the oviducts and empty cases are discarded. Fertilization takes place in the oviductal glands as the mature eggs pass through them on thir way out of the oviducts. Two secretions from the oviductal glands, together with the mucus, are used to stick the egg stalks together in strings and attach these to a substrate. Eggs are laid in shallow water. They are always attached to a substrate. On rocky shores, females find a hole, a crevice or sheltered place and they often protect their homes with shells, stones and other solid objects that they gather. Coral reefs provide suitable shelter. On sandy or muddy bottom, eggs are laid in empty mollusc shells or in man-made objects such as cans, tins, bottles, tires, boots, and amphorae . In tropical and subtropical waters, eggs are laid throughout the year. The total number of eggs laid by a female varies from 100,000 to 500,000. During egg laying and subsequent brooding, the female rarely leaves the egg mass. She usually does not feed during the entire period of spawning and brooding, which can be as long as 4-5 months at low temperatures. Egg care includes cleaning the eggs with the arm tips and directing jets of water from the funnel through the strings. Intruders, including potential prey, are pushed away, although crabs left overnight may occasionally be eaten. As a rule, females die shortly after the hatching of the last embryos after losing one-third of their pre-spawning weight.
Key reproductive features:
semelparous ; seasonal breeding ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (internal ); oviparous .
Behavior
Octopuses can learn. They can make discriminations based on visual, tactile, and chemical cues. Octopus vulgaris keeps its home hidden. The females find a hole, a crevice or sheltered place ad they often protect their homes with shells, stones, and other solid objects they gather.
Members of this species are perfectly adapted to live in very different habitats. Their capacity to conceal themselves on any substrate by varying colour, skin, texture, and posture is challenged by few other cephalopod species. In the Catalonian Sea, more particularly in the area of Banyuls and Port Vendres, Octopus vulgaris seems to undergo seasonal migrations, mainly of vertical orientation. In the early spring, large animals move inshore for spawning. The females tend to disappear during the summer; they lay eggs, brood, and die. From late summer onwards, the largest size class consists mainly of males. They leave the coastal waters in autumn or early summer; at this time the males are mature, and the females at different stages of maturation. Some of these females probably spawn in autumn, others might leave the coastal waters over the winter season and spawn in early spring, joining the animals of the first group. A third group, consisting of immature animals, invades the shallow waters in late spring. While males mature during the summer, females are likely to depart to deeper waters and return to coastal areas in spring for spawning. Doubtless, there is a vertical migratory movement in relation to spawning. Generally, the abundance of this species decreases with depth and is nearly zero at the continental shelf.
Octopus vulgaris is normally solitary and territorial. Animals make their homes near to other octopuses of similar size. If animals share a tank, each will try to occupy a home or settle down at some distance from the other inhabitants. This individualistic behavior is only interrupted during mating and spawning, but even then females brood their eggs in isolation. When not traveling in- or offshore, O. vulgaris seems to be a truly sedentary species. Underwater observations showed that the animals remain in their dens; they leave them at dusk for hunting trips and return at dawn. Excursions during the day in search of food are of shorter duration. Some octopuses may occupy the same home for a longer period while others change holes several times over a few days.
Octopus vulgaris is a typically nocturnal animal, not only in its normal habits but also in the laboratory.
Food Habits
Octopus vulgaris are active predators that feed primarily on gastropods and bivalves. Small hatchlings typically spend several weeks as active predators in the plankton before they settle down to the benthic mode of life at a size of about 0.2 grams.
Economic Importance for Humans: Positive
In 1975, some 121,000 tons of O. vulgaris were caught by fisheries. In 1976, the number was 137,000 tons.
Conservation Status
There is the potential for the overfishing of these animals, which threatens their proliferation. However, at this time, they are not at any specific risk.
Other Comments
These animals have a life span of 12 to 24 months.
For More Information
Find Octopus vulgaris information at
Contributors
Robin J. Case (author), University of Michigan.
