Giant Pacific octopus Temporal range: Pleistocene to recent [1] | |
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E. dofleini observed off Point Piños, California, at a depth of 65 m (213 ft) | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Mollusca |
Class: | Cephalopoda |
Order: | Octopoda |
Family: | Enteroctopodidae |
Genus: | Enteroctopus |
Species: | E. dofleini |
Binomial name | |
Enteroctopus dofleini (Wülker , 1910) | |
range of E. dofleini | |
Synonyms | |
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The giant Pacific octopus (Enteroctopus dofleini), also known as the North Pacific giant octopus, is a large marine cephalopod belonging to the genus Enteroctopus and Enteroctopodidae family. Its spatial distribution encompasses much of the coastal North Pacific, from the Mexican state of Baja California, north along the United States' West Coast (California, Oregon, Washington and Alaska, including the Aleutian Islands), and British Columbia, Canada; across the northern Pacific to the Russian Far East (Kamchatka, Sea of Okhotsk), south to the East China Sea, the Yellow Sea, the Sea of Japan, Japan's Pacific east coast, and around the Korean Peninsula. [3] It can be found from the intertidal zone down to 2,000 m (6,600 ft), and is best-adapted to colder, oxygen- and nutrient-rich waters. It is the largest octopus species on earth and can often be found in aquariums and research facilities in addition to the ocean. [4] [5] [6] E. dofleini play an important role in maintaining the health and biodiversity of deep sea ecosystems, cognitive research, and the fishing industry.
The giant Pacific octopus was first described in 1910 by Gerhard Wülker of Leipzig University in Über JapanischeCephalopoden. He describes the species' morphology in detail, and mentions that there seems to be much variation within the species. [7] The specific name dofleini was chosen by Gerhard Wülker in honor of German scientist Franz Theodor Doflein. [8] It was moved to genus Enteroctopus by Eric Hochberg in 1998. [9] [10] [11]
E. dofleini is distinguished from other species by its large size. It is the largest octopus species. [4] [5] [12] Adults usually weigh around 15 kg (33 lb), with an arm span up to 4.3 m (14 ft). [13] Some larger individuals have weighed-in at 50 kg (110 lb), with a radial span of 6 m (20 ft). [3] American zoologist G. H. Parker found that the largest suckers on a giant Pacific octopus are about 6.4 cm (2.5 in) and can support 16 kg (35 lb) each. [3] The only other possible contender for the largest species of octopus is the seven-arm octopus (Haliphron atlanticus), based on a 61-kilogram (134-pound), incomplete carcass estimated to have a live mass of 75 kg (165 lb). [14] [15]
E. dofleini preys on shrimp, crabs, scallops, abalones, cockles, snails, clams, lobsters, fish, squid, and other octopuses. [16] [17] [18] Food is procured with its suckers and then bitten using its tough beak of chitin. It has also been observed to catch spiny dogfish (Squalus acanthias) up to 1.2 m (4 ft) in length while in captivity. [19] 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. [20] In May 2012, amateur photographer Ginger Morneau was widely reported to have photographed a wild giant Pacific octopus attacking and drowning a seagull, demonstrating that this species is not above eating any available source of food within its size range, even birds. [21]
Scavengers and other organisms often attempt to eat octopus eggs, even when the female is present to protect them. Giant Pacific octopus paralarvae are preyed upon by many other zooplankton and filter feeders. 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. [22] In addition, the octopus (along with cuttlefish and squid) is a significant source of protein for human consumption. About 3.3 million tonnes (3.6 million short tons) are commercially fished, worth $6 billion annually. [3] Over thousands of years, humans have caught them using lures, spears, pot traps, nets, and bare hands. [23] The octopus is parasitized by the mesozoan Dicyemodeca anthinocephalum , which lives in its renal appendages. [24]
E. dofleini move through the open water using jet propulsion, which is achieved by drawing water into its body cavity and then forcefully expelling it through a siphon, creating a powerful thrust and propelling the octopus through the water at a high speed. [25] [26] When moving on the seafloor, however, the octopus crawls using its arms.
E. dofleini remain stationary or in hiding 94% of the time, usually concealed within dens, kelp, or camouflaged in their environment. [27] Otherwise, they exhibit activity throughout the day, increasingly so from midnight to the early morning. While stationary, E. dofleini hide, groom, eat, sleep, and maintain dens. E. dofleini are capable of moving vast distances to occupy new areas or habitats, with large octopuses moving further than smaller ones. Their movements are not random; they demonstrate a preference for habitats with dense kelp cover and rocky terrain suggesting a sophisticated level of habitat selection, likely optimizing foraging efficiency and minimizing exposure to predators. [28] [29] Furthermore, their movement patterns include direct relocations to new areas and central-tendency movements to return to familiar habitats. [27] This navigation behavior is influenced by the use of familiar cliff edges, substrates, and topography as well as visual navigation. [27] [30]
E. dofleini migration patterns vary depending on the population. In the eastern Pacific waters off the coast of Japan, migration coincides with seasonal temperature changes in the winter and summer. Here, E. dofleini migrate to shallower waters in the early summer and winter and offshore in the late summer and winter. [27] There is no evidence of these migration patterns in the Alaskan and northeast Pacific populations of E. dofleini.
E. dofleini are den dwellers, which serve as a central point from when they forage while also providing protection, shelter, and privacy. [25] After hunting, they bring food back to the den to feed in a safer environment and avoid predators. [31] Shells, bones, and other feeding debris pile up outside of the den, creating "den litter" that is commonly used by scientists and divers to find E. dofleini. [25] [32] [28]
Dens range across depth and substratum type including caves, holes dug beneath rock, and even trash on the ocean floor such as bottles, tires, pipes, and barrels. [25] [27] [28] Den selection is greatly influenced by foraging behavior and preferred prey. Dens made of soft substrata may be preferred in areas where bivalves are abundant while dens near rocky areas might be chosen in areas with higher crab populations. [28] The size of the den is small, usually being just large enough for the octopus to fit inside and turn around. E. dofleini beak size determines the size of the space it can fit inside, with its body being able to compress through tiny spaces as small as two inches. [25] [33] E. dofleini prefer to occupy same shelter for at least one month, often longer if possible. It is common for these octopus to leave their den for short periods of time and eventually return to re-use the same den. [29] However, over longer periods of time, E. dofleini relocate to new dens situated relatively nearby, within an average distance of 13.2 meters. [28] [29]
Unlike most other octopus species, whose lifespans normally span only one year, the giant Pacific octopus has a lifespan of three to five years. [3] They reach sexual maturity at one to two years of age. [34] Gonadal maturation has been linked to the optic gland of octopuses which has been compared functionally to the vertebrate pituitary gland. [33] These optic glands are the only endocrine glands identified in octopuses, and their secretions have been found to contribute to behaviors linked with reproduction and senescence. When removed, females no longer brood their eggs, resume feeding, increase in weight, and experience longer lifespans compared to sexually mature, brooding females who still retain their optic glands. [33]
To help compensate for its relatively short lifespan, the octopus is extremely prolific. It can lay between 120,000 and 400,000 eggs which are coated in chorion, and attached to a hard surface by the female. The spawn is intensively cared for exclusively by the female, who continuously blows water over it and grooms it to remove algae and other growths. While she fulfills her duty of parental care the female stays close to her spawn, never leaving to feed, leading to her death soon after the young have hatched. [35] The female's death is the result of starvation, as she subsists on her own body fats [36] during this period of approximately 6 months. [23] Hatchlings are about the size of a grain of rice, [37] and very few survive to adulthood. Their growth rate is quite rapid: starting from 0.03 g (0.0011 oz) and growing to 20–40 kg (44–88 lb) at adulthood, which is an increase of around 0.9% per day. [3] The giant Pacific octopus' growth over the course of a year has two sections: a faster section, from July to December, and a slower section, from January to June. [38] Because they are cool-blooded, they are able to use most of their consumed energy for body mass, respiration, physical activity, and reproduction. [23] During reproduction, the male octopus deposits a spermatophore (or sperm packet) more than 1 m (3.3 ft) long using his hectocotylus (specialized arm) in the female's mantle. The hectocotylus is found on the third arm of male octopuses and occupies the last four inches of the arm. [39] This part of the male arm anatomy contains no suckers. Large spermatophores are characteristic of octopuses in this genus. [40] The female stores the spermatophore in her spermatheca until she is ready to fertilize her eggs. One female at the Seattle Aquarium was observed to retain a spermatophore for seven months before laying fertilized eggs. [23]
Both male and female giant Pacific octopuses are semelparous, meaning they only go through one breeding cycle in their life. Analysis of egg clutches has shown evidence of polygyny and polyandry in giant Pacific octopuses, where males and females mate with multiple partners. [41] This multiple paternity potentially allows females to increase the odds of at least one of the males she mates with producing fit offspring. After mating, both the males and females stop eating and ultimately die. [39] [34] [25] After reproduction, they enter senescence, which 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. Despite active senescence primarily occurring over this period immediately following reproduction, research has shown that changes related to senescence may begin as early as the onset of reproductive behavior. [42] In early stages of senescence, which begins as the octopus enters the stage of reproduction, hyper-sensitivity is noted where individuals overreact to both noxious and non-noxious touch. As they enter late senescence, insensitivity is observed along with the dramatic physical changes described above. Changes in sensitivity to touch are attributed to decreasing cellular density in nerve and epithelial cells as the nervous system degrades. [42] Death is typically attributed to starvation, as the females have stopped hunting in order to protect their eggs; males often spend more time in the open, making them more likely to be preyed upon. [43]
Octopuses are ranked as the most intelligent invertebrates. [44] 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 with whom they frequently come in contact. These responses include jetting water, changing body texture, and other behaviors that are consistently demonstrated to specific individuals. [45] They have the ability to solve simple puzzles, open childproof bottles, and use tools. [23] The octopus brain has folded lobes (a distinct characteristic of complexity) and visual and tactile memory centers. They have about 300 million neurons. [23] They have been known to open tank valves, disassemble expensive equipment, and generally wreak havoc in labs and aquaria. [23] Some researchers even claim that they are capable of motor play [46] and having personalities. [47]
Giant Pacific octopuses are not currently under the protection of Convention on International Trade in Endangered Species of Wild Fauna and Flora or evaluated in the IUCN Red List. [48] DNA techniques have assisted in genetic and phylogenetic analysis of the species' evolutionary past. Following its DNA analysis, the giant Pacific octopus may actually prove to be three subspecies (one in Japan, another in Alaska, and a third in Puget Sound).[ citation needed ]
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. [49] Populations in Puget Sound are not considered threatened.[ citation needed ]
Regardless of these data gaps in abundance estimates, future climate change scenarios may affect 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, effects on other trophic levels, and RNA editing.[ citation needed ]
Fraud is an issue in the seafood industry, with species names being switched by accident or on purpose, as in the case of using the name of a more expensive species for a cheaper one. Cephalopods, in particular, lose distinguishing characteristics during food processing, making them much harder to identify. One study developed a multiplex PCR assay to distinguish between three prevalent octopus species in the Eastern Pacific, namely, the giant Pacific octopus, the big blue octopus, and the common octopus, in order to accurately identify these species and help to prevent seafood fraud. [50] Combined with lack of assessment and mislabeling, tracking the species's abundance is nearly impossible. Scientists have relied on catch numbers to estimate stock abundance, but the animals are solitary and difficult to find. [23] Sites like The Monterey Bay Aquarium Seafood Watch can help people to responsibly consume seafood, including the giant Pacific octopus. Seafood Watch lists giant Pacific octopus in either the "Buy" or "Buy, but be aware of concerns" categories depending on the geographical location of the catch. [51]
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 population density (or decreased available habitat/den space) [52] Because their blue blood is copper-based (hemocyanin) and not an efficient oxygen carrier, octopuses favor and move toward cooler, oxygen-rich water. This dependency limits octopus habitat, typically to temperate waters 8–12 °C (46–54 °F). [3] If seawater 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 octopuses, 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. [53] Fish and octopuses move from the deep towards the shallow water for more oxygen. Females do not leave, and die with their eggs at nesting sites. Warming seawater temperatures promote phytoplankton growth, and annual dead zones have been found to be increasing in size. [23] To avoid these dead zones, octopuses must move to shallower waters, which may be warmer in temperature and less oxygen-rich, trapping them between two low-oxygen zones.[ citation needed ]
Increased seawater temperatures also increase metabolic processes. The warmer the water, the faster octopus eggs develop and hatch. [3] After hatching, the paralarvae swim 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 affect critical timing for food availability. [54] One study found that higher water temperatures accelerated all aspects of reproduction and even shortened lifespan by up to 20%. [55] Other studies concur that warming climate scenarios should result in higher embryo and paralarvae mortalities. [56]
The burning of fossil fuels, deforestation, industrialization, and other land-use changes cause increased carbon dioxide levels in the atmosphere. The ocean absorbs an estimated 30% of emitted anthropogenic CO2. [57] 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. [58] The prey base that octopuses prefer (crab, clams, scallops, mussels, etc.) are negatively impacted by ocean acidification, and may decrease in abundance. Shifts in available prey may force a change in octopus diets to other, nonshelled organisms.[ citation needed ]
Because octopuses have hemocyanin as copper-based blood, a small change in pH can reduce oxygen-carrying capacity. A pH change from 8.0 to 7.7 or 7.5 will have life-or-death effects on cephalopods. [23]
Researchers have found high concentrations of heavy metals and PCBs in tissues and digestive glands, which may have come from these octopus' preferred prey, the red rock crab (Cancer productus). [59] These crabs bury themselves in contaminated sediments and eat prey that live nearby. [3] What effects these toxins have on octopuses are unknown, but other exposed animals have been known to show liver damage, changes in immune systems, and death.[ citation needed ]
Potential changes in octopus populations will affect upper and lower trophic levels. [54] Lower trophic levels include all prey items, and may fluctuate inversely with octopus abundance. Higher trophic levels include all predators of octopuses, and may fluctuate with octopus abundance, although many may prey upon a variety of organisms. Protection of other threatened species may affect octopus populations (the sea otter, for example), as they may rely on octopuses for food. Some research suggests that fishing other species has aided octopus populations, by taking out predators and competitors.[ citation needed ]
An octopus is a soft-bodied, eight-limbed mollusc of the order Octopoda. The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttlefish, and nautiloids. Like other cephalopods, an octopus is bilaterally symmetric with two eyes and a beaked mouth at the centre point of the eight limbs. The soft body can radically alter its shape, enabling octopuses to squeeze through small gaps. They trail their eight appendages behind them as they swim. The siphon is used both for respiration and for locomotion, by expelling a jet of water. Octopuses have a complex nervous system and excellent sight, and are among the most intelligent and behaviourally diverse of all invertebrates.
A squid is a mollusc with an elongated soft body, large eyes, eight arms, and two tentacles in the orders Myopsida, Oegopsida, and Bathyteuthida. Like all other cephalopods, squid have a distinct head, bilateral symmetry, and a mantle. They are mainly soft-bodied, like octopuses, but have a small internal skeleton in the form of a rod-like gladius or pen, made of chitin.
A cephalopod is any member of the molluscan class Cephalopoda such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot. Fishers sometimes call cephalopods "inkfish", referring to their common ability to squirt ink. The study of cephalopods is a branch of malacology known as teuthology.
The giant squid is a species of deep-ocean dwelling squid in the family Architeuthidae. It can grow to a tremendous size, offering an example of abyssal gigantism: recent estimates put the maximum size at around 12–13 m (39–43 ft) for females and 10 m (33 ft) for males, from the posterior fins to the tip of the two long tentacles. The mantle of the giant squid is about 2 m long, and the length of the squid excluding its tentacles rarely exceeds 5 m (16 ft). Claims of specimens measuring 20 m (66 ft) or more have not been scientifically documented.
The vampire squid is a small cephalopod found throughout temperate and tropical oceans in extreme deep sea conditions. The vampire squid uses its bioluminescent organs and its unique oxygen metabolism to thrive in the parts of the ocean with the lowest concentrations of oxygen. It has two long retractile filaments, located between the first two pairs of arms on its dorsal side, which distinguish it from both octopuses and squids, and places it in its own order, Vampyromorphida, although its closest relatives are octopods. As a phylogenetic relict, it is the only known surviving member of its order.
The California two-spot octopus, often simply called a "bimac", is an octopus species native to many parts of the Pacific Ocean including the coast of California. One can identify the species by the circular blue eyespots on each side of its head. Bimacs usually live to be about two years old. They are closely related to Verrill's two-spot octopus. In 2015, the genome was sequenced.
Enteroctopus is an octopus genus whose members are sometimes known as giant octopuses.
The shortnose spurdog also known as the piked spurdog is a small shark located primarily off the coast of Southern Australia and South Africa. The shortnose spurdog's size is dependent on the sex of the animal. The female shortnose spurdog is consistently larger than the male shortnose spurdog and will typically measure out to about 56.41 cm (1.85 ft) while the male shortnose spurdog will typically only measure out to about 44.36 cm in length (1.46 ft) which means the female shortnose spurdog is over 10 cm longer than the male shortnose spurdog. Some females can even measure up to 78 cm which is over 2.5 feet long. The life span of spurdog's can be quite long with females typically living longer than males. The average life span of a female shortnose spurdog is 0–29 years old while the male life span is 0-26 though it is estimated that a female can live up to 46 years while a male can only live up to 33. Females also take longer to reach sexual maturity than males and on average are not fertile until they are over 15 years of age. 7 years longer than the 8 years it takes males to reach maturity. The shortnose spurdog's eat a variety of items but primarily favor cephalopods such as squid and octopuses for their meals. Other organisms that have been found in their stomachs include fish, hermit crabs, sponges, brittle stars, the remains of sea lion and even primary producers such as algae.
Octopus rubescens is the most commonly occurring shallow-water octopus on much of the North American West Coast and a ubiquitous benthic predator in these habitats. Its range extends from the southern Gulf of California to at least the Gulf of Alaska, but may also occur in the western Pacific Ocean. O. rubescens occurs intertidally to a depth of 300 m (980 ft).
Octopus cyanea, also known as the big blue octopus or day octopus, is an octopus in the family Octopodidae. It occurs in both the Pacific and Indian Oceans, from Hawaii to the eastern coast of Africa. O. cyanea grows to 16 cm in mantle length with arms to at least 80 cm. This octopus was described initially by the British zoologist John Edward Gray in 1849; the type specimen was collected off Australia and is at the Natural History Museum in London.
Enteroctopus megalocyathus, also known as Patagonian red octopus (EN), Pulpo del sur (Chile) and Pulpo colorado (Argentina); is a medium-sized octopus, and the type species for the genus Enteroctopus.
In zoology, deep-sea gigantism or abyssal gigantism is the tendency for species of deep-sea dwelling animals to be larger than their shallower-water relatives across a large taxonomic range. Proposed explanations for this type of gigantism include necessary adaptation to colder temperature, food scarcity, reduced predation pressure and increased dissolved oxygen concentrations in the deep sea. The harsh conditions and inhospitality of the underwater environment in general, as well as the inaccessibility of the abyssal zone for most human-made underwater vehicles, have hindered the study of this topic.
The seven-arm octopus, also known as the blob octopus or sometimes called septopus, is one of the two largest known species of octopus; the largest specimen ever discovered had an estimated total length of 3.5 m (11 ft) and mass of 75 kg (165 lb). The only other similarly large extant species is the giant Pacific octopus, Enteroctopus dofleini.
Aggregata is a genus of parasitic alveolates belonging to the phylum Apicomplexa.
Franz Theodor Doflein was a German zoologist known for his studies of animal ecology.
Pinnoctopus cordiformis is a species of octopus found around the coasts of New Zealand. It is one of the most common species of octopus in the country.
Octopus maya, known colloquially as the Mexican four-eyed octopus, is a shallow water octopus that can be found in the tropical Western Atlantic Ocean. It is common to sea grass prairies and coral formations. The species was initially discovered in an octopus fishery in Campeche Mexico, where its close external resemblance to Octopus vulgaris led to its mistaken grouping with the other species. O. maya makes up 80% of octopus catch in the Yucatán Peninsula, while O. vulgaris makes up the remaining 20%.
The larger Pacific striped octopus (LPSO), or Harlequin octopus, is a species of octopus known for its intelligence and gregarious nature. The species was first documented in the 1970s and, being fairly new to scientific observation, has yet to be scientifically described. Because of this, LPSO has no official scientific name. Unlike other octopus species which are normally solitary, the LPSO has been reported as forming groups of up to 40 individuals. While most octopuses are cannibalistic and have to exercise extreme caution while mating, these octopuses mate with their ventral sides touching, pressing their beaks and suckers together in an intimate embrace. The LPSO has presented many behaviors that differ from most species of octopus, including intimate mating behaviors, formation of social communities, unusual hunting behavior, and the ability to reproduce multiple times throughout their life. The LPSO has been found to favor the tropical waters of the Eastern Pacific.
Wunderpus photogenicus, the wunderpus octopus, is a small-bodied species of octopus with distinct white and rusty brown coloration. 'Wunderpus' from German "wunder" meaning 'marvel or wonder'.
Bathypolypus sponsalis, commonly called the globose octopus, is a deep sea cephalopod that can be found in both the eastern Atlantic Ocean and the Mediterranean Sea. It possesses many morphological traits adapted to a deep sea environment, including large eggs, reduced gills, no ink sac, and subgelatinous tissues. A distinguishing factor are the relatively large reproductive organs. Their diet consists of predominantly crustaceans and molluscs, but they sometimes consume fish as well. Bathypolypus sponsalis usually dies quickly after reproduction and only spawns once in their lifetime. Sexually mature females have a mantle length of at least 34 mm and sexually mature males have a mantle length of about 24 mm. Juveniles are white and transition to dark brown then to dark purple once maturity is reached.