Overview

Comprehensive Description

Biology/Natural History: The 3rd right arm of the male of this species has a large hectocotylus, about 1/5 the length of the arm (photo). The hectocotylus is used in transferring the male's spermatophore, or package of sperm, which may be up to a meter long, to the female. The hectocotylus may be left within the mantle of the female during the process. Eggs, which look like small whitish grapes, are laid throughout the year but mainly in the winter. When the female has eggs she attaches them to the roof of a cave and guards them until they hatch (5-7 months). She may lay 35,000 to 70,000 eggs in a single clutch. Hatching is mainly in early spring, and the young are pelagic for one to several months before settling. The young are sometime seen swimming near the surface. Lifespan is thought to be 4-5 years. Prey include crustaceans (shrimp and crabs), mollusks (scallops, clams, abalones, moon snails, small octopus), and fish (rockfish, flatfish, sculpins). The octopus are often captured in crab traps, where they are trying (successfully) to steal the crabs. Females can be cannibalistic. The Seattle Aquarium recently observed an octopus catching the spiny dogfish Squalus acanthias, and in 2005 we found the picked-clean skeleton of a dogfish on the shellheap outside an octopus den (photo). The species accumulates a large pile of shells and crab carapaces outside the den, which is usually under a boulder or in a rocky crevice. They quickly kill crabs by rasping a tiny hole (1 mm or less in diameter) through the carapace (photo), probably with their radula, then presumably injecting poison, perhaps with their beak. Several species may be attracted to their shell pile (midden), including Pycnopodia helianthoides and the snail Amphissa columbiana. Predators include seals, sea otters, dogfish sharks, lingcod, and man. Parasites include the mesozoans Dicyemenna abreida and Conocyema deca, which live in the kidney.

This octopus is said to be capable of inflicting a painful bite but I have never seen anyone bitten, even when wrestling them off the rocks. They seem much less ready to bite than is O. rubescens.

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The skin of this octopus is not smooth; instead it has extensive skin folds and large, truncate papillae. Color often some shade of dark red or reddish brown but can change color rapidly (for example to a light mottled greenish). May have white spots on the dorsal mantle and on the arm web in front of the eyes, but no "eyespots" as are seen on O. bimaculatus farther south. May grow very large, with a mantle length over 20 cm, body weight to 272 kg, and arm spread to 9 m. This is the world's largest known octopus.
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Distribution

Geographic Range

Giant Pacific octopuses, Enteroctopus dofleini, are found throughout the Pacific Ocean. They have been documented as far north as the Alaskan Aleutian Islands and as far south as the Baja California region of Mexico. This species ranges as far northeast as Japan.

Biogeographic Regions: pacific ocean (Native )

  • Scheel, D. 2002. Characteristics of habitats used by Enteroctopus dofleini in Prince William Sound and Cook Inlet, Alaska. Marine Ecology, 23/5: 185-206.
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Geographical Range: Bering Sea to California; Northern Asia, Japan (and presumably Hong Kong)

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Physical Description

Morphology

Physical Description

Giant Pacific octopuses are larger than any other species of octopus. Specimens have weighed as much as 272 kg and measured 9.6 m in radius. However, most reach an average weight of 60 kg with a dorsal mantle length of 50 to 60 cm. Giant Pacific octopuses are usually reddish in color but are able to change color and texture when threatened or for camouflage. The dorsal mantle is shaped like a sack and contains the brain, reproductive organs, digestive organs, and eyes. Giant Pacific octopuses have two eyes, one on each side of their head, which provide extremely acute vision. Giant Pacific octopuses also have four pairs of arms that extend from the mantle. Each pair is covered with up to 280 suckers, which contain thousands of chemical receptors.

Average mass: 60 kg.

Other Physical Features: ectothermic

  • Anderson, R., J. Wood, R. Byrne. 2002. Octopus senescence: the beginning of the end. Journal of Applied Animal Welfare Science, 5/4: 275-283.
  • Schwab, I. 1987. A well armed predator. British Journal of Ophthalmology, 87/7: 812.
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Type Information

Holotype for Polypus gilbertianus Berry, 1912
Catalog Number: USNM 214320
Collection: Smithsonian Institution, National Museum of Natural History, Department of Invertebrate Zoology
Sex/Stage: male;
Preparation: Isopropyl Alcohol
Year Collected: 1903
Locality: Behm Canal, Naha Bay, Indian Point N 18 Deg. E, 0.9 Mile, Alaska, United States, Gulf of Alaska, North Pacific Ocean
Depth (m): 75 to 245
Vessel: Albatross R/V
  • Holotype: Berry, S. 1912. Bull. Bur. Fish., Wash. 30(1910): 284-286, pls. 35-37.
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Look Alikes

How to Distinguish from Similar Species: Octopus rubescens is smaller, with mantle length less than 10 cm and weight less than 200 g; its skin has small, pointed papillae but not the large skin folds found on O. dofleini.
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Ecology

Habitat

coastal to shelf
  • UNESCO-IOC Register of Marine Organisms
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Giant Pacific octopuses are generally found in tidal pools and up to depths of 110 m, although they can also reside in deeper waters of up to 1,500 m. They often live in dens or lairs, under boulders, and in rock crevices. Ideal habitat for this species includes a soft substrate of mud, sand or gravel that includes large boulders for creating dens. Giant Pacific octopuses are found in greater densities near dense kelp fields. Members of this species are ectothermic, and their metabolism is dependent upon water temperature. Optimal water temperatures for giant Pacific octopuses range between 7 and 9.5 degrees Celsius.

Range depth: 0 to 1500 m.

Habitat Regions: saltwater or marine

Aquatic Biomes: benthic ; coastal

  • Wildscreen. 2010. "North Pacific giant octopus (Enteroctopus dofleini)" (On-line). ARKive: Images of Life on Earth. Accessed February 02, 2011 at http://www.arkive.org/north-pacific-giant-octopus/enteroctopus-dofleini/#text=All.
  • Scheel, D., A. Lauster, T. Vincent. 2007. Habitat ecology on Enteroctopus dofleini from middens and live prey surveys in Prince William Sound, Alaska. Pp. 434-458 in N Landman, R Davis, R Mapes, eds. Cephalopods Present and Past: New Insights and Fresh Perspectives. Dordrecht, The Netherlands: Springer.
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Depth range based on 150 specimens in 2 taxa.
Water temperature and chemistry ranges based on 46 samples.

Environmental ranges
  Depth range (m): 0 - 799
  Temperature range (°C): 2.304 - 11.845
  Nitrate (umol/L): 5.774 - 43.616
  Salinity (PPS): 31.893 - 34.331
  Oxygen (ml/l): 0.303 - 6.561
  Phosphate (umol/l): 0.883 - 3.284
  Silicate (umol/l): 10.574 - 102.211

Graphical representation

Depth range (m): 0 - 799

Temperature range (°C): 2.304 - 11.845

Nitrate (umol/L): 5.774 - 43.616

Salinity (PPS): 31.893 - 34.331

Oxygen (ml/l): 0.303 - 6.561

Phosphate (umol/l): 0.883 - 3.284

Silicate (umol/l): 10.574 - 102.211
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

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Depth Range: Intertidal to 100 (180) m

Habitat: Primarily rocky subtidal; occasionally low intertidal or on sand

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Trophic Strategy

Food Habits

Giant Pacific octopuses are considered generalist foragers. They return to their den in order to consume their prey, and they deposit the prey's remains at the entrance of their den. This collection of skeletal remains is known as a middens. Examination of middens indicates that the diet of giant Pacific octopuses is primarily composed of clams, crabs, fish, and squid. Giant Pacific octopuses are visual hunters that utilize a variety of hunting strategies including stalking, chasing, and camouflaging themselves in order to ambush prey. They possesses a well-developed sense of vision, allowing them to coordinate the use of all eight arms to attack their victim. Members of this species also use different methods to prepare meals for consumption. One method includes pulling the protective shell apart in order to reach the meat contained inside. Another method involves crushing prey with their strong beak located in the center of its appendages. The most common method of obtaining food, however, involves drilling a hole in the prey's shell, in which an octopus injects its toxic saliva.

Animal Foods: fish; mollusks; aquatic crustaceans

Primary Diet: carnivore (Molluscivore )

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Associations

Ecosystem Roles

Giant Pacific octopuses do not specialize on any one particular species of prey and are not the main source of food for any particular predator. They do, however, serve as host to some dicyemid mesozoans. Dicyemennea nouveli is a large, conical-shaped species that reaches up to 12,000 um in length. Dicyemennea nouveli inserts the pointed anterior end of its body into the folds of the renal appendages of giant Pacific octopuses. Other members of g. Dicyemennea are also found in shallow-water cephalopods.

Commensal/Parasitic Species:

  • Furuya, H. 2008. Redescription of Dicyemennea nouveli (Phylum: Dicyemida) from Enteroctopus dofleini (Mollusca: Cephalopoda: Octopoda). The Journal of Parasitology, 94/5: 1064-1070.
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Predation

Giant Pacific octopuses avoid predation by remaining in a protective den, camouflaging itself, or hiding among kelp. Although juveniles are eaten by a variety marine life, adult giant Pacific octopuses have few predators other than humans, which have hunted this species to use as food and as bait for Pacific halibut. Giant Pacific octopuses are known for their ability to release an ink cloud, although they rarely do so as a direct form of defense. Instead, they tend to fight off predators with their arms. Once released, they use their propulsion abilities to jet away. As giant Pacific octopuses escape, they then expel a cloud of ink as a screen, allowing them to seek safe refuge.

Known Predators:

Anti-predator Adaptations: cryptic

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Life History and Behavior

Behavior

Communication and Perception

Each pair of arms of giant Pacific octopuses has up to 280 suckers, which have thousands of chemical receptors. These provide an acute sense of touch and taste, which this species use to help detect prey. Typically calm animals, giant Pacific octopuses are unusually adept at navigating by using landmarks in the wild and at adapting objects as tools. They are the only invertebrate known to use their well-developed vision to learn through observation. Giant Pacific octopuses are considered extremely intelligent, partially do to their larger-than-average brain-to-body weight ratio. Individuals in captivity are known for having having unique temperaments and personalities, ranging from playful to destructive. Their high level of intelligence and desire to interact with human caretakers have earned captive members of this spices a reputation as notorious escape artists.

Perception Channels: visual ; tactile ; chemical

  • Mather, J. 2008. Cephalopod consciousness: behavioural evidence. Conciousness and Cognition, 17/1: 37-48.
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Life Cycle

Development

The lifespan of giant Pacific octopuses is characterized by a fast growth period that continues throughout its entire life of 4 to 5 years. Larvae hatch from a cluster of eggs and are on average 9.5 to 10.1 mm in length. The larvae, with limited swimming ability, move to the surface to begin a planktonic existence that lasts 1 to 3 months. At the end of the planktonic stage, juveniles descend to the benthos where they undergo rapid growth. Giant Pacific octopuses continue to grow until they reproduce. Within 3 months of breeding, males normally undergo a period of senescence and die. Symptoms of senescence in this species include reduced food intake, retraction of skin around the eyes, aimless movement (wandering) and lesions that do not heal. Females that survive brooding undergo a similar period of senescence and die within weeks of the eggs hatching.

  • Kubodera, T. 1991. Distribution and abundance of the early stages of octopus, Octopus dofleini wulker, 1910 in the north Pacific. Bulletin of Marine Science, 49: 235-243.
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Life Expectancy

Lifespan/Longevity

Giant Pacific octopuses on average live 4.5 to 5 years in the wild. A similar lifespan has been observed for members this species held in public aquariums.

Average lifespan

Status: wild:
4.5 to 5 years.

Average lifespan

Status: captivity:
4.5 to 5 years.

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Reproduction

Male reproductive organs of great Pacific octopuses are enclosed inside the mantle cavity within a genital bag. Spermatozoa are encapsulated in a spindle-shaped spermatophoric sac. Males utilizes a hectocotylized arm, a specialized tentacle used for the transfer of sperm, to insert the two spermatophores (each 1 m in length) into an oviduct located in the mantle of the female. The balloon part of the spermatophore remains inside the oviduct while the remainder of the sac hangs from the female. Eventually, the sac bursts and releases millions of spermatozoa. The entire mating process takes 2 to 3 hours. Giant Pacific octopuses are polygynous.

Mating System: polygynous

Giant Pacific octopuses breed throughout the year, though spawning peaks in winter. Males may breed with several females, but females mate only once in their lifetime. Over several days, females lay 20,000 to 100,000 rice-shaped eggs (avg. 50,000) in grape-like clusters of 200 to 300 eggs each. These clusters are hung from the ceiling of the den. Females remain with the eggs throughout the entire brooding period, guarding them from predators and using her syphon to aerate and clean the clusters. Hatching can take anywhere from 150 days to almost 1 year depending on water temperature. Cooler temperatures delay the development of the embryo and therefore lengthen incubation time.

Breeding interval: Male giant Pacific octopuses may breed with several females once reaching maturity, but females mate only once in their lifetime.

Breeding season: Giant Pacific octopuses breed year-round.

Range number of offspring: 20,000 to 100,000.

Average number of offspring: 50,000.

Average time to independence: 0 minutes.

Range age at sexual or reproductive maturity (female): 3 to 5 years.

Range age at sexual or reproductive maturity (male): 3 to 5 years.

Key Reproductive Features: semelparous ; year-round breeding ; sexual ; fertilization (Internal ); broadcast (group) spawning; oviparous

Female giant Pacific octopuses remain with their eggs throughout the entire brooding period, guarding them from predators and using their syphon to aerate and clean the clusters. Females do not leave the den during this period, not even to eat. Females die during the brooding period or shortly thereafter, and males die within three months of breeding. Therefore, there is no post-hatching parental investment evident in giant Pacific octopuses.

Parental Investment: pre-hatching/birth (Provisioning: Female, Protecting: Female)

  • Wildscreen. 2010. "North Pacific giant octopus (Enteroctopus dofleini)" (On-line). ARKive: Images of Life on Earth. Accessed February 02, 2011 at http://www.arkive.org/north-pacific-giant-octopus/enteroctopus-dofleini/#text=All.
  • Anderson, R., J. Wood, R. Byrne. 2002. Octopus senescence: the beginning of the end. Journal of Applied Animal Welfare Science, 5/4: 275-283.
  • High, W. 1976. The giant Pacific octopus. Marine Fisheries Review, 38/9: 17-22.
  • Kubodera, T. 1991. Distribution and abundance of the early stages of octopus, Octopus dofleini wulker, 1910 in the north Pacific. Bulletin of Marine Science, 49: 235-243.
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Molecular Biology and Genetics

Molecular Biology

Statistics of barcoding coverage: Enteroctopus dofleini

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 182
Specimens with Barcodes: 183
Species With Barcodes: 1
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Barcode data: Enteroctopus dofleini

The following is a representative barcode sequence, the centroid of all available sequences for this species.


There are 2 barcode sequences available from BOLD and GenBank.  Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.  See the BOLD taxonomy browser for more complete information about this specimen and other sequences.

ACATTATATTTTATTTTTGGAATTTGATCAGGTTTACTAGGTACATCATTA---AGATTAATAATTCGAACAGAACTAGGACAACCTGGATCTTTACTAAATGAT---GATCAACTTTATAACGTTATTGTTACTGCCCACGCTTTTGTAATAATTTTCTTTTTAGTTATACCCGTAATAATTGGAGGATTTGGAAACTGATTAGTCCCTTTAATA---TTAGGAGCTCCAGATATAGCATTCCCACGAATAAACAATATAAGATTTTGATTACTTCCCCCCTCTTTAACTCTCCTATTAACTTCAGCAGCAGTAGAAAGAGGAGCAGGAACAGGTTGAACTGTATACCCTCCATTATCTAGAAATTTAGCCCATATAGGTCCTTCTGTAGATCTA---GCAATTTTTTCCCTTCATTTAGCAGGTATTTCCTCTATTTTAGGAGCTATTAATTTCATCACAACTATTATTAATATACGATGAGAAGGGATACAAATAGAACGTCTTCCACTATTTGTATGATCTGTTCTAATTACAGCAGTTCTTCTTCTACTATCTTTACCAGTATTAGCAGGT---GCCATTACTATACTTCTTACTGATCGTAACTTCAATACAACTTTTTTTGACCCAAGAGGAGGAGGAGATCCTATTCTATATCAACATTTA------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------TTT
-- end --

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Conservation

Conservation Status

Giant Pacific octopuses are not considered at risk by the IUCN Red List, CITES, or the US Federal List of Endangered Species. Although this spices is commercially fished in some areas, this does not appear to be greatly affecting population sizes.

US Federal List: no special status

CITES: no special status

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Relevance to Humans and Ecosystems

Benefits

Economic Importance for Humans: Negative

There are no known adverse effects of giant Pacific octopuses on humans.

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Economic Importance for Humans: Positive

Giant Pacific octopuses were commonly used as bait for Pacific halibut during the late 1950s and 1960s, though this is no longer a common practice. In some ares, this species is commercially fished and is eaten in some countries in the Pacific.

Positive Impacts: food

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Wikipedia

Enteroctopus dofleini

Enteroctopus dofleini, also known as the giant Pacific octopus (GPO) or North Pacific giant octopus, is a large marine cephalopod belonging to the phylum Mollusca, and genus Enteroctopus. Its spatial distribution includes the coastal North Pacific, along California, Oregon, Washington, BC, Alaska, Russia, northern Japan and Korea.[1] They can be found from the intertidal zone down to depths of 2,000 m (6,600 ft), and is best adapted to cold, oxygen-rich water. It is arguably the largest octopus species, based on a scientific record of a 71 kg (156 lb) individual weighed live.[2] The alternative contender is the seven-arm octopus (Haliphron atlanticus) based on a 61 kg (134 lb) carcass estimated to have a live mass of 75 kg (165 lb).[3][4] However, a number of questionable size records would suggest E. dofleini is the largest of all octopus species by a considerable margin.[5]

History[edit]

The octopus (/ˈɒktəpʊs/ or /ˈɒktəpəs/; plural: octopuses, octopi, or octopodes) were named by ancient Greeks, meaning "eight foot". The preferred plural is octopuses, although octopi and octopodes are also recognized. Octopus were depicted on Cretan and Minoan coins (1650 to 1500 BC and 1450 to 1375 BC) and were painted onto jars in the Mycenaenera (circa 1200 to 1100 BC).[6] Cephalopods have been around for 500 million years, although octopus ancestors were in the Carboniferous seas around 300 million years ago.[6] The oldest octopus fossil, Pohlsepia can be found at the Field Museum in Chicago.[6]

Size and description[edit]

Close-up of E. dofleini showing the longitudinal folds on the body and the paddle-like papillae

All cephalopods have bilateral symmetry, a shell gland, a mantle, and well-developed head with sucker covered arms. The octopus has eight arms, each of which has two rows of suckers. Many of the suckers are lined with papillae or hooks for adhesion.

Close up of suckers

[7] The web between the arms can be expanded to form a parachute-like structure to capture prey[7] In the center of the arms is a mouth, containing beak and radula (toothed-tongue).

Schematic lateral aspect of octopod features

Cephalopods have a paralytic and digestive toxin in two salivary glands to aid in opening prey.[7] Water is pulled into the mantle and over gills or lamellae for oxygen uptake, and can be ejected forcefully through the siphon for jet propulsion. They can get up to speeds of 25 miles per hour, but only for short sprints. They tend to use their arms as legs, and slowly crawl along the bottom.[6] The siphon is also used to expel ink for escaping predators. The entire body of the octopus is compressible, so that they are able to fit through any opening slightly bigger than the size of their beak (the only hard part of their body). Their arms are muscular hydrostats, which lengthen, contract and contort.[6] Octopuses are poikilothermic or cool-blooded, have three hearts and blue copper-based blood.[1]

The mantle of the octopus is spherical in shape and contains most of the animal's major organs. By contracting or expanding tiny pigment-containing sacs within cells known as chromatophores, an octopus can change the color of its skin, giving it the ability to blend into the environment. Sub categories of chromatophores include iridophores (reflective platelets) and leucophores (refractive platelets).[1] Octopuses are also able to alter their skin texture, providing even better camouflage. Dermal muscles in the octopus's skin can create a heavily textured look through papillation, or cause skin to appear smooth.[8] All of these abilities are under nervous system control.

E. dofleini is distinguished from other species by its sheer size. Adults usually weigh around 15 kg (33 lb), with an arm span of up to 4.3 m (14 ft).[9] The larger individuals have been measured at 50 kg (110 lb) and have a radial span of 6 m (20 ft)[10] However, highly questionable records of specimens up to 272 kg (600 lb) in weight with a 9-m (30-ft) arm span have been reported.[11] Guinness World Records lists the biggest as 136 kg (300 lb) with an arm span of 9.8 m (32 ft)[1] American zoologist G.H. Parker found that the largest suckers on a GPO is about 6.4 cm (2.5 in) and each can support 16 kg (35 lb) each.[1] Octopuses also have chemotaxis, or the ability to taste by touch.

Diet[edit]

E. dofleini commonly prey upon shrimp, crabs, scallops, abalone, clams, lobsters, and fish. Food is procured with its suckers and then bitten using its tough "beak" of chitin. They have also been observed to catch spiny dogfish (Squalus acanthias) up to four feet in length while in captivity.[12] Additionally, consumed carcasses of this same shark species have been found in giant Pacific octopus middens in the wild, providing strong evidence of these octopuses preying on small sharks in their natural habitat.[13] In May 2012, amateur photographer Ginger Morneau was widely reported to have photographed a wild giant Pacific octopus attacking and drowning a seagull, which would demonstrate the species is not above eating any available source of protein within its size range, even birds.[14]

Predators[edit]

Scavengers and other organisms often attempt to eat octopus eggs, even when the female is present to protect them. As paralarvae, many other zooplankton and filter feeders prey upon this life stage. As adults, marine mammals, such as harbor seals, sea otters, and sperm whales depend upon the giant Pacific octopus as a source of food. Pacific sleeper sharks are also confirmed predators of this species.[15] In addition, the octopus (along with cuttlefish and squid) are major sources of protein for human consumption. 3.3 million tons are commercially fished, worth 6 billion annually.[1] Over thousands of years, humans have caught them via lures, spears, pot traps, nets and using only bare hands.[6]

Takoyaki stall in Nishi-Magome, Tokyo

Lifespan and reproduction[edit]

The giant Pacific octopus is considered to be long-lived compared to other species, with lifespans that average 3–5 years in the wild. Many other octopus go through a lifespan in one year, from egg to end of life.[1] To make up for its relatively short life span, the octopus is extremely prolific. It can lay 120,000 up to 400,000 eggs which are intensively cared for by the females. The female stops eating during this care and her life ends soon after the eggs hatch.[16] Eggs are coated in chorion, and the female attaches the eggs to a hard surface. She continuously blows water over the eggs, and grooms them of algae and other growths. Eggs hatch in approximately 6 months.[6] Hatchlings are about the size of a grain of rice,[17] and very few survive to adulthood. Their growth rate is incredibly high. Starting from 3/100ths of a gram and growing to 20–40 kg at adulthood, is approximately 0.9% of growth a day.[1] Because they are cool-blooded, they are able to convert most of consumed energy into body mass, respiration, activity and reproduction.[6]

Hectocotylus arm of an octopod

During reproduction, the male octopus deposits a spermatophore (or sperm packet) more than one meter long using his hectocotylus (specialized arm) in the female's mantle. Large spermatophores are characteristic of octopuses in this genus.[5] The female stores the spermatophore in her spermatheca until she is ready to fertilize her eggs. One female GPO at the Seattle Aquarium was observed to hold onto the spermatophore for seven months before laying fertilized eggs.[6]

Giant Pacific octopuses are semelparous; they are characterized by a single reproductive episode before death. After reproduction they enter a stage called senescence. This involves obvious changes in behavior and appearance, including a reduced appetite, retraction of skin around the eyes giving them a more pronounced appearance, increased activity in uncoordinated patterns, and white lesions all over the body. While the duration of this stage is variable, it typically lasts about one to two months. Death is typically attributed to starvation as the females stop hunting and protect their eggs; males often spend more time in the open making them more likely to be preyed upon.[18]

Intelligence[edit]

Giant Pacific Octopus (Octopus dofleini)

Octopuses are ranked as the most intelligent invertebrates.[19] In the third century AD, Roman natural historian Claudius Aelianus wrote "Mischief and craft are plainly seen to be the characteristics of this creature."[20][20] Giant Pacific octopuses are commonly kept on display at aquariums due to their size and interesting physiology, and have demonstrated the ability to recognize humans that they frequently come in contact with. These responses include jetting water, changing body texture, and other behaviors that are consistently demonstrated to specific individuals.[21] They have the ability to solve simple puzzles, open childproof bottles and use "tools".[6] The octopus brain has folded lobes (a distinct characteristic of complexity), visual and tactile memory centers. They have about 300 million neurons.[6] They have been known to open tank valves, disassemble expensive equipment and generally wreak havoc in labs and aquariums.[6] Some researchers even claim that they are capable of motor play[20] and having personalities.[7] Some claim that octopuses are psychic, as Paul was made famous by predicting all seven winning teams in the 2010 FIFA World Cup, although this is not scientifically supported.[6]

Conservation and climate change[edit]

Giant Pacific octopus are not currently under the protection of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) or evaluated in the IUCN Red List (International Union for Conservation of Nature).[22] The giant Pacific octopus has not been assessed by the Monterey Bay Aquarium Seafood watch, although other octopus species are listed.[23] Combined with lack of assessment and mislabeling, tracking species abundance is nearly impossible. Scientists have relied on catch numbers to estimate stock abundance, but as the animals are solitary and difficult to find, many numbers are just estimates.[6] DNA techniques have assisted in genetic and phylogenetic analysis of the species' evolutionary past. After DNA analysis, it has been suggested that the giant Pacific octopus may actually be three subspecies (one in Japan, one in Alaska, and a third in Puget Sound).

In Puget Sound, the Washington Fish and Wildlife Commission adopted rules for protecting the harvest of giant Pacific octopuses at seven sites, after a legal harvest caused a public outcry.[24] Populations in Puget Sound are not considered threatened.

Regardless of these data gaps in abundance estimates, it can be speculated that future climate change scenarios may effect these organisms in different ways. Climate change is complex, with predicted biotic and abiotic changes to multiple processes including

  • Oxygen limitation
  • Reproduction
  • Ocean acidification
  • Toxins
  • Affects on other trophic levels
  • RNA editing

Oxygen limitation[edit]

Octopuses have been found to migrate for a variety of reasons. Using tag and recapture methods, scientists found they move from den to den in response to decreased food availability, change in water quality, increase in predation, or increased density (or decreased available habitat/den space)[25] Because their blue blood is copper-based (hemocyanin) and not an efficient oxygen carrier, octopus favor and move toward cooler oxygen-rich water. This dependency limits octopus habitat, typically in temperate waters 8-12 degrees Celsius (46-54 degrees Fahrenheit)[1] If sea water temperatures continue to rise, these organisms may be forced to move to deeper cooler water.

Each fall In Washington's Hood Canal (a habitat for many octopus), phytoplankton and macroalgae die and create a dead zone. As these micro-organisms decompose, oxygen is used up in the process and has been measured to be as low as 2 parts per million (ppm). This is a state of hypoxia. Normal levels are measured at 7-9 ppm.[26] Fish and octopus move from the deep towards the shallow water for more oxygen. Females do not leave, and die with their eggs at nesting sites. Warming sea water temperatures promote phytoplankton growth, and annual dead zones have been found to be increasing in size.[6] To avoid these dead zones, octopuses must move to shallower waters which may be warmer in temperature and less oxygen-rich, trapping the organism between two low oxygen zones.

Reproduction[edit]

Increased sea water temperatures also increase metabolic processes. The warmer the water, the faster octopus eggs develop and hatch.[1] After hatching, the paralarvae swim up to the surface to join other plankton, where they are often preyed upon by birds, fish and other plankton feeders. Quicker hatching time may also effect critical timing with food availability.[27] One study found that higher water temperatures accelerated all aspects of reproduction and even shortened lifespan by up to 20%.[28] Other studies concur that warming climate scenarios result in higher embryo and paralarvae mortalites.[29]

Ocean acidification[edit]

The burning of fossil fuels, deforestation, industrialization and other land-use changes cause increased carbon dioxide levels in the atmosphere. It has been estimated that the ocean absorbs approximately 30% of emitted anthropogenic CO.2[30] As the ocean absorbs CO2, it becomes more acidic and lowers in pH. Ocean acidification lowers available carbonate ions, which is a building block for calcium carbonate (CaCO3). Calcifying organisms use calcium carbonate to produce shells, skeletons and tests.[31] The prey base that octopus prefer (crab, clams, scallops, mussels, etc.) will be negatively impacted by ocean acidification, and may decrease in abundance. Shifts in available prey may force a change upon octopus diet to other non-shelled organisms.

Because octopus have hemocyanin as copper-based blood, a small change in pH can reduce oxygen carrying capacity. Roger Hanlon found that pH changes from 8.0 to 7.7 or 7.5 will have life or death effects on cephalopods.[6]

Toxins[edit]

Dr. Roland Anderson, an octopus specialist, found high concentrations of heavy metals and PCBs in tissues and digestive glands. He suggests that these high concentrations were obtained from their preferred prey, red rock crab (Cancer productus).[32] These crabs bury themselves in contaminated sediments and eat prey that live nearby.[1] It is unknown to what effect these toxins have on octopus, but other exposed animals have been known to show liver damage, changes in immune system, and death.[33]

Effects on other trophic levels[edit]

Potential changes in octopus populations will majorly effect upper and lower trophic levels.[27] Lower trophic levels include all prey items (see above), and may fluctuate inversely with octopus abundance. Higher trophic levels include all predators of octopus (see above), and may fluctuate inversely with octopus abundance, although many may prey upon a variety of organisms. Protection of other threatened species may effect octopus populations (the sea otter, for example), as they may rely on octopus for food. Some research suggests that fishing other species have aided octopus populations, by taking out predators and competitors. Because of the lack of agreement, more research is needed to understand how populations will be effected.

RNA editing[edit]

Research has shown that some octopuses exhibit the ability to alter speeds of sodium and potassium ion movement across cell membranes, allowing them to live in very cold water. Joshua Rosenthal, at the University of Puerto Rico's Institute of Neurobiology has found that they have altered protein synthesis, and can speed up potassium channels in cold water, to keep up with sodium ion exchange. He is now looking into whether individuals can alter their protein synthesis in response to changing temperatures, or if it's done over long-term adaptations. If changes are possible by the individual, octopuses may be able to adapt quickly to changing climate scenarios.[6]

See also[edit]

The Cephalopod Page Monterey Bay Seafood Watch

References[edit]

  1. ^ a b c d e f g h i j k Cosgrove, James. Super Suckers, The giant pacific octopus. BC: Harbour Publishing. ISBN 978-1-55017-466-3. 
  2. ^ Cosgrove, J.A. 1987. Aspects of the Natural History of Octopus dofleini, the Giant Pacific Octopus. M.Sc. Thesis. Department of Biology, University of Victoria (Canada), 101 pp.
  3. ^ O'Shea, S. (2004). "The giant octopus Haliphron atlanticus (Mollusca : Octopoda) in New Zealand waters". New Zealand Journal of Zoology 31 (1): 7–13. doi:10.1080/03014223.2004.9518353. 
  4. ^ O'Shea, S. (2002). "Haliphron atlanticus — a giant gelatinous octopus". Biodiversity Update 5: 1. 
  5. ^ a b Norman, M. 2000. Cephalopods: A World Guide. Hackenheim, ConchBooks, p. 214. ISBN 978-3-925919-32-9
  6. ^ a b c d e f g h i j k l m n o p q Courage, Katherine Harmon (2013). Octopus!. USA: The Penguin Group. ISBN 978-1-59184-527-0. 
  7. ^ a b c d Mather, J.A.; Kuba, M.J. (2013). "The cephalopod specialties: complex nervous system, learning and cognition". Canadian Journal of Zoology 91 (6): 431–449. 
  8. ^ Mather, J. A.; Kuba, M. J. (2013). "The cephalopod specialties: Complex nervous system, learning, and cognition1". Canadian Journal of Zoology 91 (6): 431. doi:10.1139/cjz-2013-0009.  edit
  9. ^ Smithsonian National Zoological Park: Giant Pacific Octopus
  10. ^ Cosgrove, James (5/6/14). Super Suckers. BC: Harbour Publishing. ISBN 978-1-55017-466-3. 
  11. ^ High, W.L. 1976. The giant Pacific octopus. U.S. National Marine Fisheries Service, Marine Fisheries Review 38(9): 17-22.
  12. ^ "Octopus Eats Shark". Google Video. Retrieved 13 November 2012. 
  13. ^ Walla Walla University Marine Invertebrates Key: Giant Pacific Octopus
  14. ^ McCulloch, S. 2012. B.C. woman nets fame for photos of octopus eating seagull. National Post, May 3, 2012.
  15. ^ Sigler, M. F.; L. B. Hulbert, C. R. Lunsford, N. H. Thompson, K. Burek, G. O’Corry-Crowe, A. C. Hirons (24 Jul 2006). "Diet of Pacific sleeper shark, a potential Steller sea lion predator, in the north-east Pacific Ocean". Journal of Fish Biology (USA: Wiley-Blackwell) 69 (2): 392–405. doi:10.1111/j.1095-8649.2006.01096.x. 
  16. ^ Scheel, David. "Giant Octopus: Fact Sheet". Alaska Pacific University. Retrieved 13 November 2012. 
  17. ^ "Giant Pacific Octopus (Octopus dofleini)". NPCA. Archived from the original on 21 November 2008. Retrieved 13 November 2012. 
  18. ^ Anderson, R. C.; Wood, J. B.; Byrne, R. A. (2002). "Octopus Senescence: The Beginning of the End". Journal of Applied Animal Welfare Science 5 (4): 275–283. doi:10.1207/S15327604JAWS0504_02. PMID 16221078.  edit
  19. ^ Anderson, R. C. (2005). How smart are octopuses? Coral Magazine 2: 44–48.
  20. ^ a b c Tzar, Jennifer. "Through the Eye of an Octopus". Discover. 
  21. ^ Anderson, R. C.; Mather, J. A.; Monette, M. Q.; Zimsen, S. R. M. (2010). "Octopuses (Enteroctopus dofleini) Recognize Individual Humans". Journal of Applied Animal Welfare Science 13 (3): 261–272. doi:10.1080/10888705.2010.483892. PMID 20563906.  edit
  22. ^ "IUCN Red List of Threatened Species. Version 2013.2.". Retrieved 12 May 2014. 
  23. ^ "Monterey Bay Seafood Watch". 
  24. ^ "Giant Pacific Octopus Rulemaking Process". Retrieved 12 May 2014. 
  25. ^ Mather, J.A.; Resler, S.; Cosgrove, J.A. (1985). "Activity and Movement patterns of Octopus dofleini.". Journal of Marine Behavior and Physiology. 11: 301–14. 
  26. ^ Mather, J.A. (2010). Octopus: The Ocean's Intelligent Invertebrate. Portland. London.: J.B. Timber Press. ISBN 978-1-60469-067-5. 
  27. ^ a b Andre, J; Haddon, M.; Pecl, G.T. (2010). "Modeling climate-change induced nonlinear thresholds in cephalopod population dynamics.". Global change biology 16 (10): 2866–2875. 
  28. ^ Forsythe, J.W.; Hanlon, R.T. (1988). "Effect of temperature on laboratory growth, reproduction, and life span of Octopus bimaculoides". Marine Biology 98: 369-379. 
  29. ^ Repolho, Tiago (2014). "Developmental and physiological challenges of octopus (Octopus vulgaris) early life stages under ocean warming". Journal of Comparative Physiology B 184 (1): 55-64. 
  30. ^ Guinotte, J.M.; Fabry, V.J. (2008). "Ocean acidification and its potential effects on marine ecosystems.". Annals of the New York Academy of Sciences 1134 (1): 320–342. 
  31. ^ Gazeau, F.; Quiblier, C.; Jansen, J.M.; Gattuso, J.P.; Middelburg, J.J.; Heip, C.H. (2007). "Impact of elevated CO2 on shellfish calcification". Geophysical Research Letters 34 (7). 
  32. ^ Scheel, D.; Anderson, R. (2012). "Variability in the diet specialization of Enteroctopus dofleini (Cephalopoda: Octopodidae) in the eastern Pacific examined from midden contents.". American Malacological Bulletin 30 (2): 267–279. 
  33. ^ "PCBs". 
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