Common Octopus

Medium to large sized; animal chunky in appearance. Arms stout, of about equal length and thickness, dorsal pair of arms slightly shorter; shortened right arm III of males hectocotylized by modification of tip into a very small, spoon-shaped ligula; ligula index (length of ligula expressed as percentage of length of hectocotylized arm) less than 2.5; 7 to 11 gill lamellae on outer side of of gill, including terminal lamella.

Worldwide in temperate and tropical waters; limits unknown.

Maximum total length 1.2 m in females and to 1.3 m in males; maximum weight 10 kg; common to 3 kg. In the western Mediterranean, mantle length at first maturity is about 9.5 cm in males, 13.5 cm in females.

A benthic, neritic species occurring from the coastline to the outer edge of the continental shelf(in depths from 0 to 200 m), where it is found in a variety of habitats, such as rocks, coral reefs, and grass beds.It is inactive in waters of 7°C and colder. Throughout its distribution range, this species is known to undertake limited seasonal migrations, usually overwintering in deeper waters and occurring in shallower waters during summer. In the western Mediterranean, large mature or maturing individuals migrate inshore in early spring, followed later on by smaller, immature individuals. These two groups begin their retreat into deeper waters by August/September and November/ December respectively. Similar migration patterns are found in other sea areas. Two spawning peaks per year can be observed for this species throughout its distributional range: in the Mediterranean and the Inland Sea of Japan, the first occurs in April/ May corresonding to the group migrating in shore in spring (most important in the Mediterranean) and the second in October, corresponding to the group migrating in autumn (most important in Japan); off West Africa, around Cape Blanc, the first spawning peak occurs in May/June and the second (more important) in September. Females may produce between 120 000 and 400 000 eggs little longer than 2 mm, which they deposit in strings in crevices or holes, usually in shallow waters. Spawning may extend up to 1 month. During the brooding period (25 to 65 days), females almost cease feeding and many die after the hatching of the larvae. The hatchlings are pelagic, but settle to benthic life after about 40 days at a minimum size of approximately 12 mm. In the Inland Sea of Japan, common octopus reaches about 1 kg weight in 4 months; in the western Mediterranean it grows from 3 to about 20 cm in 17 months. A von Bertalanffy growth expression is given for the Mediterranean and eastern Atlantic populations by Guerra (1979). Food consists of bivalves and crustaceans.Larvae and juveniles are preyed upon by albacore (Thunnus alalunga) etc., and adults by benthic finfishes.

World catches attributed to O. vulgaris declined from peaks in the late sixties (more than 100 000 t per year) to 20 000 to 30 000 t in recent years (FAO, 1983). Part of the nonidentified world catches of Octopus oscillating between 120 000 and 160 000 t annually, also pertain to this species (including part of the nearly 45 000 t caught by Japan in the Inland Sea, Fishing Area 61, and most of the catches (between 40 000 and 50 000 t) taken by Spanish vessels on the Sahara Banks off West Africa, Fishing Area 34). The species is highly desirable and commands high prices throughout its distributional range and supports artisanal as well as industrial fisheries. It is taken mainly with lures, hooks and lines, pots, spears and otter trawls. In the Inland Sea of Japan, some 12 000 to 17 000 pots are laid out annually to provide shelter and enhance egg conservation as a measure to safeguard recruitment of the fishable stock. This species is marketed fresh, frozen and dried salted, mostly for human consumption.The total catch reported for this species to FAO for 1999 was 34 262 t. The countries with the largest catches were Mexico (19 081 t) and Italy (8 844 t).