Common Octopus – Octopus Vulgaris
The common octopus – Octopus Vulgaris is mostly found on continental shelves, such as in the U.S South Atlantic Bight. It is a highly valued species regularly taken as a bycatch in wire mesh taps put for Black Sea Bass, Centropristis striata. Though it is not a targeted species, its high price is prompting some fishermen to consider doing small-scale fishing undertakings. The other reason for their potentiality is due to the spawn measures put in place to control the commercial exploitation of finfishes in the U.S, limiting the number of species that can be targeted in a certain season (Rudershausen, n.d). The gear set for octopus is not expensive in comparison to those of others and it is easy to deploy too. There are various species of octopus and this paper studies the Common Octopus with a special interest in its habitat, nutrition, reproduction, and its behaviors.
The Common Octopus belongs to the Domain Eukarya, Kingdom Animalia, Phylum Mollusca, Class Cephalopoda, Order Octopoda, Suborder Incirrina, Family Octopodidae, Subfamily Octopodinae, Genus Octopus, and Species Octopus Vulgaris.
There are more than 650 species in the class Cephalopoda and some include nautilus, squid, octopus, and cuttlefish. This species has a wide distribution rate globally with a lot of abundance in the Mediterranean Sea, Eastern Atlantic Ocean, and Japanese waters (Norman et al 2004). They commonly live in tropical, subtropical, and temperate waters to the cold deep of abyssal trenches between 100 and 150 meters deep. It is more active and has an optimal growth at about 170 C. Octopus Vulgaris does not live in polar and sub polar areas (Rosenthal, n.d). They dig holes in the sediments or form burrows by pressing into clefts. They use most of their time hiding.
They have a bilaterally symmetrical body type. All species of octopus have eight arms, with each having two rows of circular suckers and have no tentacles (Rosenthal, n.d). The arms can be extended, retracted, grasped, and feel independently from the others. They have no shell on either inside or out, and they have three hearts – one for blood circulation and the other two for passing blood over the gills for oxygenation. The bag-shaped body of an octopus is covered by the mantle, which is a muscular organ consisting of cuticle underneath the epidermis. The mantle encloses organs like kidneys, liver, gills, stomach, intestines, brain, and reproductive organs. On top of the octopus’s head, there are two eyes with structural equivalency to that of human beings, which have a very good sight. It grows to reach 1 to 3 feet long including its arms. They have smooth skin.
In addition to protecting the inner organs, the mantle can also be expanded to draw water into the cavity and then contracted to eject it via a narrow opening known as the siphon. This action gives an octopus a way for rapid movements. The cavity also has gills or ctenidia and it uses them to haul out oxygen from the water for respiratory functions. The nervous system of an octopus is exceedingly developed and has a brain that is within the cartilaginous cranium and the mantle muscles do not protect it but it is located within the head. The head has other structures, such as the brachial nerves and a buccal mass with a well-built beak.
Octopus Vulgaris mainly feed on gastropods and bivalves like mussels, Scallops, Clams, Crabs, Crawfish, and Lobsters. Octopus seizes its prey by either waiting in its den or going to hunt. Its sensory skills, such as eyesight, touch, and smell help to give it a signal on the type of available prey and the excellent procedure to catch it. It can disguise itself as a sea wind or set itself in a web or umbrella-like position on suspected prey areas. The octopus bites the prey and injects venom, which paralyzes the animal. It then injects an enzyme that starts to break the animal’s protein, thus weakening and softening it over some time.
Octopus Vulgaris has both sexes – that is male and female. During the reproduction, the male move toward the female who first tries to resist before complying. The male octopuses have a modified arm namely, hectocotylus and it helps in copulation with the female octopus. A ventral channel that extends to the whole length of the arm transmits the spermatophores from the male octopus to the female oviduct. This initiates reproduction exchange, which can continue for an hour or more. After mating, the male octopus ceases to eat and eventually dies. Once the internal fertilization completes, the female lays teardrop-shaped eggs from the oviduct. The secretion from the oviductal glands and the mucus connects the eggs together into a gelatinous string that forms a cluster of dozens or hundreds that are attached to a hard substrate within the female den (Case, n.d). The female octopus lays about 100,000 and 500,000 eggs.
The female octopus remains on close-range guarding the eggs for maximum survival of the developing young ones. They spend all of their energy aerating the eggs by cleaning them through siphoning of clean water. For a period of about 4 to 5 months, the female octopus does not go out for feeding, which causes it to lose about one-third of its total weight and dies immediately after the eggs hatch. Octopus Vulgaris has a life span of about 12 to 24 months.
Behavior and Unique Characteristics
They use camouflage as a protective measure by resembling other creatures or blending to take the color of the surroundings. This is made possible as they possess’ chromatophores, reflective cells, and photophores. All these help it to change how it looks making it difficult to spot the species in its natural habitat. The Chromatophores, found within the epidermis releases wavelengths with yellow, orange, red, brown, and black pigments. The mantle can turn translucent and allow the internal organs, such as the ink sac to be visible as a dark spot. By use of some of these components, the Octopus has the ability to crypto resulting in background resemblance, countershading and concealing the shadow, and deceiving resemblance (Case, n.d).
Other than cryptic, the octopus uses three other ways for its protection from potential predators. It uses jet propulsion, swimming, and burying it on the sediments. It uses inking, which is a behavior that allows it to discharge a cloud of ink that resembles its shape thereby confusing the predator and it gets a chance to spurt away. It flashes colors and displays clouds to frighten potential predators when it is in threat. Their postural and locomotive capacities are an effective tool for the camouflaging procedure. The erected arm and the look of the mantle, while the animal sits on a coral reef, is a defensive mechanism that can prevent its detection by a potential predator. The experience of the beak can also provide an enduring impression to a predator or any other enemy on its territory.
Octopus Vulgaris Threat Status
The Octopus Vulgaris is not an endangered species. This is because it exists in abundance in the Atlantic Ocean and Japanese waters. Furthermore, after mating, a female octopus lays thousands of eggs, which it protects until they hatch. Though their parents do not protect them – because they die immediately after the eggs hatched, the survival rate is low because they are eaten by other sea creatures but those that survive mature to reproduce due to their protective mechanisms and because they spend most of their time in their dens. However, there is a potential threat of being overfished by the anglers who are considering them as potential and commercially viable thus hindering their proliferation.
Reason for Choosing Common Octopus
Octopus Vulgaris and other similar species have been on the focus of more research and being observed. Generally, octopuses are presumably to be one of the most intelligent invertebrates. They have both long and shorter-term memories and can be trained on how to solve problems by trial and error methods. They can be trained on how to unlock a jar and are able to navigate mazes in a quicker way demonstrating their ability for cognitive learning. Once they are able to solve a particular problem, octopuses have been found to remember the solution and solve the problem repeatedly.
Case R. J. [n.d.]. Octopus vulgaris [internet]. University of Michigan: Museum of Zoology[cited 2014 April 12]. Available from <http://animaldiversity.ummz.umich.edu/accounts/Octopus_vulgaris/>
Rosenthal MK. [n.d]. Common Octopus: Octopus Vulgaris [internet]. [cited 2014 April 12].
Available from <http://www1.broward.edu/~ssimpson/rosenthal.htm>
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