Common Octopus, Octopus vulgaris
Common Octopus, Octopus vulgaris. Underwater photographs taken in the coastal waters off Bonaire, Caribbean Netherlands, December, 2019. Photograph and identification courtesy of Bob Hillis, Ivins, Utah.
Common Octopus, Octopus vulgaris
Phylogeny: The Common Octopus Octopus vulgaris Cuvier, 1797, is a member of the Octopodidae family of octopuses. The genus Octopus is one of twenty-three genera in this family, and there are seventy-three species in this genus. In Mexico they are known as Pulpo Común and Pulpo Patón.
Morphology: The Common Octopus is a medium to large sized animal with bilateral symmetry with a chunky appearance with eight stout tentacles that are equal in length and thickness with the dorsal pair of arms being slightly shorter. They do not have an internal skeleton. The head, with very large eyes on top, and foot are at one end of an elongated body. The head includes the mouth and the brain. The foot contains 4 pairs of tentacles with the first 2 are utilized for mobility and the other 6 are used to forage for food. The interior surfaces of the arms are covered with circular adhesive suckers that allow the octopus to attach itself to or manipulate objects. The body is made of soft flexible tissue that allows for facile lengthening and contraction of the animal. They possess a siphon that is utilized for respiration and locomotion that occurs by expelling a jet of water. The 8 tentacles trail behind as they swim. They have 3 hearts, 1 to circulate blood throughout the body, and 2 that pump blood through each of the two gills. The blood contains copper rich hemocyanin that transports oxygen. They have excellent eyesight, hearing and sense of touch and a complex nervous system. They are dimorphic with males having a shorter third right arm that has a modified tip into a very small spoon-shaped ligula. Their mantles can be up to 25 cm (10 inches) in length and the males have a maximum of 1.3 m (4 feet 3 inches) in total length versus 1.2 m (3 feet 11 inches) for females. They can weight up to 10 kg (22 pounds). They grow rapidly, mature early and are very short-lived.
Habitat and Distribution: The Common Octopus is bottom dwelling reef-associated solitary animal that is found within coral reefs, rocks and grass beds near the coastline within the tidal and subtidal zones to the depths up to 213 m (700 feet) in waters that range in temperature between 13oC (56oF) and 28oC (79oF). They will move to deeper waters during warm water episodes. When they move it is along the seafloor. They spend a significant amount of their times in dens within a defined home range. They access oxygen from the water through both their gills and via absorption through their skin. They are prone to die offs if oxygen levels drop below 10% and if salinity drops due to the intrusion of fresh water. The Common Octopus is a circumglobal species that is found in all temperate and tropical seas. In Mexico they are found in all coastal waters of the Atlantic; in the Pacific they have a limited distribution being found from Acapulco, Guerrero, south to Guatemala. They are known to make seasonal migrations to deep waters during cold water episodes.
Diet: Common Octopus are highly predatory normally hunting at dusk utilizing camouflage when hunting they consume crabs, crustaceans, mollusks and polychaete worms utilizing a venomous toxin to help capture prey. They utilize a “moving rock” strategy where the octopus mimics a rock and then inches along undetected matching the movement of the surrounding water. They bring prey back to their dens having the ability to go direct without having to retrace their tracks. In turn the juveniles are preyed upon by abalone and various benthic fishes. The adults are preyed upon on various cephalopods, cetaceans, pinnipeds, sea birds, sea otters and humans. They have the ability to change colors and blend into the background to help avoid predation; they also can release a large cloud of ink that fowls the predators sense of smell that allows the octopus to escape and seek shelter. These octopi can also detach one tentacle which remains alive, distracts the predator and flee. They have the ability to replace lost limbs. The Common Octopus are highly intelligent animals that have long- and short-term memory skills with the ability of distinguish brightness, patterns, shape, and size between objects. They are intelligent enough to be able to board fishing boats and open holds to obtain crabs.
Reproduction: Common Octopuses are gonophoric with each female producing between 120,000 and 400,000 eggs that are deposited in strings in crevices and holes within the reef in shallow water. The eggs are brooded for 25 to 65 days until they hatch and then the parents provide no additional care. The males, that have a specialized arm called a hectocotylus for reproduction, normally die after spawning and the females die shortly after the eggs hatch. The larvae are pelagic and settle out to the bottom in 40 days but less than 1% of the eggs will survive and become adult octopuses. They have life spans of between 1 and 2 two years.
Ecosystem Interactions: Common Octopuses are known to host endoparasitic protozoa, cestodes, and nematodes, as well as ectoparasitic copepods. The Octopidis Mysid Shrimp, Heteromysis octopodis, throughout its range, engages in a commensal living space arrangement with Common Octopuses. It is unknown if a similar shrimp does so in Mexican waters.
Human interactions: From a conservation perspective the Common Octopus are currently considered to be of Least Concern with stable, widely distributed populations. They are fish commercially being caught by hook and line, lures, pots, spears, traps, otter trawls with global commercial sales estimated at 35,000 tons per annum with more than half originating in Mexico. They are marketed fresh, frozen, and dried salted for human consumption. They are considered to be highly desirable and command high prices. The Common Octopus is currently being farmed off the west coast of Spain where subadults are collected and placed in floating cages, then fattened for four months via selective feeding until they reach 3.0 kg (6.6. pounds) in weight and then processed for market. A complete live cycle of this octopus under culture conditions has been achieved but is not yet viable commercially due to large mortality rates. In general, the Common Octopus try to avoid humans but will bite if provoked, and although they are venomous the venom is not lethal to humans. They can be found in large public aquariums but are notorious escape artists. They are currently of significant interest in biological research due their problem-solving skills.
Synonyms: Octopus albus, Octopus bitentaculatus, Octopus brevitentaculatus, Octopus cassiopea, Octopus cassiopeia, Octopus coerulescentes, Octopus heteropus, Octopus maculatus, Octopus moschatus, Octopus niger, Octopus octopodia, Octopus pilosus, Octopus rabassin, Octopus ruber, Octopus rugosus, Octopus tetradynamus, Octopus tritentaculatus, Octopus troscheli, Octopus troschelii, Octopus tuberculatus, Octopus tuberculatus, Sepia octopus, Sepia polypus, and Sepia rugosa.