North Pacific giant octopus (Enteroctopus dofleini)

Description

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North Pacific giant octopus fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
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North Pacific giant octopus description

True to its name, the North Pacific giant octopus is the largest of all octopus species ^{(2) (3) (4)}, and, along with other cephalopods (a group of molluscs that contain the octopuses, squid and cuttlefish), it is considered one of the most intelligent of all invertebrates ⁽⁵⁾. The body, or ‘mantle’, is generally reddish-brown, and it is usually darker in the male than in the female ⁽²⁾. During mating, white spots also become visible on the male’s mantle ⁽⁶⁾. When disturbed or threatened, special pigment cells in the skin, called chromatophores, may become activated, and cause the mantle to change colour to white or red ^{(2) (7) (8)}.

Size

Length: 3 – 5 m ⁽²⁾

Weight

10 – 50 kg ⁽²⁾

North Pacific giant octopus biology

The North Pacific giant octopus relies heavily on its highly developed senses; each of its four pairs of arms is covered with up to 280 suckers, and each individual sucker contains thousands of chemical receptors that give it an acute sense of touch and taste ⁽⁴⁾, which it uses to detect its prey ⁽¹¹⁾. It is an active predator, feeding mainly at night on a wide array of species that include crustaceans (particularly crabs and lobsters), molluscs, small fish and other octopuses ^{(2) (3) (8)}. Capable of using several different techniques to access the soft flesh inside its hard-bodied prey, the North Pacific giant octopus may pull apart the shell, or bite it open with its hard ‘beak’. Where a prey item is too difficult to be pulled or bitten apart, it may use a special drilling technique, whereby the salivary papilla, an organ that is covered in small teeth, is used to drill a hole in the shell and secrete a toxin. The toxin paralyses the prey and dissolves the connective tissue that attaches the animal to its shell, making it easier for the North Pacific giant octopus to feed on the contents inside ^{(4) (8) (11)}.

The North Pacific giant octopus may reproduce at any time during the year, with a spawning peak during the winter months ⁽³⁾. Usually a solitary species, the male and the female will only come together for a short time during mating ⁽²⁾. The male has a specially modified arm, known as the hectocotylus, which is used to deposit a packet of sperm, called a spermatophore, inside the mantle cavity of the female ^{(2) (3) (4) (8)}. After mating, the female will lay between 20,000 to 100,000 eggs over a period of several days. The eggs are laid in strings that hang inside a rocky den, and from then on the female will wash and aerate the eggs with a stream of water from the siphon, and will groom the eggs to ensure they remain free of parasites. Depending on water temperature (which controls the rate of development of the eggs), the incubation period can last up to eight months, during which time the female does not feed. The female dies shortly after the eggs hatch ^{(2) (3) (4) (8)}.

North Pacific giant octopus range

Occurs in coastal waters of the North Pacific Ocean, ranging from California, north to Alaska and the Aleutian Islands, and across to Japan ^{(3) (8) (9)}.

North Pacific giant octopus habitat

Distributed throughout the benthic zone (the region at the bottom of the ocean), the North Pacific giant octopus is usually most abundant in areas with large boulders and rocky reefs, using the crevices in rocks to make dens in which it shelters ^{(2) (10)}. It is known to inhabit a range of depths, from shallow waters of less than 5 metres, down to depths of 1,500 metres ^{(4) (10)}.

North Pacific giant octopus status

This species has yet to be classified by the IUCN.

North Pacific giant octopus threats

Although there is very little information on the population status of the North Pacific giant octopus, it is currently not considered threatened. In some areas it is commercially fished, but at present levels this does not appear detrimental to the population ^{(8) (12)}. It is possible that some populations that live in shallow coastal waters may be susceptible to habitat change caused by human activities ⁽¹⁰⁾.

North Pacific giant octopus conservation

There are currently no conservation actions targeted at this species; however, the North Pacific giant octopus is known from several Marine National Parks along the Pacific coast of North America ⁽¹²⁾.

Find out more

To find out more about the North Pacific giant octopus, see:

• BBC Wildlife Finder
  http://www.bbc.co.uk/nature/species/North_Pacific_Giant_Octopus

To find out more about Marine National Parks in North America, see:

• National Parks Conservation Association:
  http://www.npca.org/

Authentication

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Glossary

Crustaceans

Diverse group of arthropods (a phylum of animals with jointed limbs and a hard chitinous exoskeleton) characterised by the possession of two pairs of antennae, one pair of mandibles (parts of the mouthparts used for handling and processing food) and two pairs of maxillae (appendages used in eating, which are located behind the mandibles). Includes crabs, lobsters, shrimps, slaters, woodlice and barnacles.

Incubation

The act of incubating eggs, that is, keeping them warm so that development is possible.

Invertebrates

Animals with no backbone, such as insects, crustaceans, worms, molluscs, spiders, cnidarians (jellyfish, corals, sea anemones), echinoderms, and others.

Mantle cavity

The fold in the mantle (body wall) of molluscs that encloses a space that contains the gills, and which functions as a respiratory chamber. In some molluscs the mantle cavity is also used as a brooding chamber for the young, and in cephalopods and some bivalves, the mantle cavity is used in locomotion.

Molluscs

A diverse group of invertebrates, mainly marine, that have one or all of the following; a horny, toothed ribbon in the mouth (the radula), a shell covering the upper surface of the body, and a mantle or mantle cavity with a type of gill. Includes snails, slugs, shellfish, octopuses and squid.

Parasites

Organisms that derive food from, and live in or on, another living organism at the host’s expense.

Siphon

In molluscs, a tube-like structure through which water passes into or out of the mantle cavity.

Spawning

The production or depositing of large quantities of eggs in water.

References

1. Integrated Taxonomic Information System (ITIS) (July, 2010)
   http://www.itis.gov/
2. Burnie, D. (2001) Animal. Dorling Kindersley, London.
3. The Giant Octopus Web Page (July, 2010)
   http://marine.alaskapacific.edu/octopus/
4. Smithsonian National Zoological Park (July, 2010)
   http://nationalzoo.si.edu/
5. The Cephalopod Page (July, 2010)
   http://www.thecephalopodpage.org/
6. Anderson, R.C., Cosgrove, J.A., Jensen, G.C. and Lewand, K.O. (2003) Observations on mating of giant Pacific octopuses. In: Droscher, T. and Fraser, D.A. (Eds.) 2003 Georgia Basin/Puget Sound Research Conference, Proceedings (December 2003). Vancouver, British Columbia.
7. Campbell, A. and Dawes, J. (2004) Encyclopedia of Underwater Life. Oxford University Press, Oxford.
8. MarineBio (July, 2010)
   http://marinebio.org/species.asp?id=60
9. Vincent, T.L.S., Scheel, D. and Hough, K.R. (1998) Some aspects of diet and foraging behaviour of Octopus dofleini (WULKER, 1910) in its northernmost range. Marine Ecology, 19(1): 13-29.
10. Scheel, D. (2002) Characteristics of habitats used by Enteroctopus dofleini in Prince William Sound and Cook Inlet, Alaska. Marine Ecology, 23(3): 185-206.
11. Hanlon, R.T. and Messenger, J.B. (1996) Cephalopod Behaviour. Cambridge University Press, Cambridge. 
12. National Parks Conservation Association (July, 2010)
    http://www.npca.org/marine_and_coastal/marine_wildlife/octopus.html