Octopus Vulgaris

By Robin J. Case

Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Order: Octopoda
Suborder: Incirrina
Family: Octopodidae
Subfamily: Octopodinae
Genus: Octopus
Species: Octopus vulgaris


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.

These animals are found in the following types of habitat:
temperate ; tropical .

Aquatic Biomes:
benthic ; reef ; coastal .

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
Number of offspring
100000 to 500000

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.