Octopus - Species

Species

With over 200 known species we cannot list them all here, but here are the most commonly known:

COMMON ATLANTIC OCTOPUS (OCTOPUS VULGARIS)

The Common Atlantic octopus can grow to reach 10’ or 3m in length when the body and arms are measured together. They have a smooth body that changes colour considerably to blend in with their surroundings. Common colours include pink, red/brown, grey and even white with a green tinge. Their arms are very thick and measure around 4 times the length of the body with two alternating rows of suckers.

This species can be found in the coral reefs around Florida, Mexico and the West Indies near to the low-tide line and close to the shore. They are a reserved species and tend to hide during the day in crevices and under large rocks.

GIANT PACIFIC OCTOPUS (OCTOPUS DOFLEINI)

Known to grow as large as 23 feet and 150 lbs this is the largest of the known Octopus species. Although studied in laboratories, the natural history is still not fully documented. The life cycle differs slightly from the average octopus, and appears to be between four and five years. Eggs are laid several times a year, primarily in the winter hatching some 5-7 months later. They are found primarily on the North Pacific Ocean continental shelf, from southern California upwards along the coastline of the Pacific Northwest, as well as across the Aleutians and down to Japan.

It can reach lengths of 16’ or 5m when the body and arms are measured together and can weigh anywhere up to 600 pounds. It has a round body with deeply wrinkled skin and a red/brown colour that is changeable depending on its circumstances. The arms are around 4 times the length of its body and have two alternating rows of white suckers.

The Giant Pacific octopus is common all the way from Alaska to California and is fished along the entire coast. It lives in tide-pools and along rocky areas up to a depth of over 500m. It feeds on a variety of sea-life including fishes, clams, crabs, shrimps and even smaller species’ of octopus. In addition to man, it has a number of other predators including seals, sharks and other large fishes.

PACIFIC RED OCTOPUS (OCTOPUS REUBESCENS)

The red octopus is nocturnal, and can change color. It has small white spots on the mantle and web in front of the eyes and is small with a mantle normally not exceeding 10 cm. They normally live in kelp beds but the young are often washed ashore and may be found under rocks or in sandy mud flats. Average life expectancy of 2-3 years.

BLUE RINGED OCTOPUS

The Blue-ringed octopus is reported to be the most poisonous of all cephalopods. There are thought to be around 10 different species of Blue-ringed octopus with the most commonly known being:

• The Lesser Blue-ringed octopus (Hapalochlaena maculosa)
• The Greater Blue-ringed octopus (Hapalochlaena lunulata)

These tiny octopuses get there name from the distinctive blue rings that only become visible when the octopus is startled.

A few facts about the Lesser Blue-ringed octopus

1. It is the more common of the two species and the larger.
2. It has a body length of about 5cm, an arm length of about 10cm and it generally weighs less than 30grams.
3. At rest the octopus has a grey/beige colour with numerous patches of light brown. These are known as maculae and are positioned in patterns on the mantle, web and legs of the octopus. During an attack or when something irritates an octopus these patches darken in colour and bright blue rings appear within them. Normally there are upwards of 50 blue rings measuring around 2mm in diameter.
4. They are only found in the waters of southern Australia up to a depth of 50m.

A few facts about the Greater Blue-ringed octopus

1. It is the smaller of the two species with a body size of less than 5cm and arms around 7cm.
2. It is called the Greater Blue-ringed octopus because its rings measure around 8mm and cover the upper or dorsal surface of the mantle and the legs. Even when the octopus is at rest faint blue outlines are still visible.
3. It is characterised by a bright blue horizontal line that runs straight through the eye.
4. They are commonly found around the coral reefs of northern Australia and everywhere else between Australia and Japan at depths of below 20m.

Greater Blue-ringed Octopus Hapalochlaena lunulata

Both species eat small crabs and shrimps. They use one of their two poisons to the kill their prey although the exact method they use to do this is still not known. It could be that they bite their victim or that they expel toxic saliva into the water that then acts on the prey. The Blue-ringed octopus has a second poison that is much more toxic and is used as a self defence mechanism against predators.

Normally this species of octopus is not aggressive and they would rather blend into the background than confront a predator. However if they have no other choice then the Blue-ringed octopus release a neuromuscular venom that causes the victim to become paralysed. The toxin they release is fatal as it paralyses all of the muscles in the body including those in the walls of the heart. However if artificial respiration and heart massage are used immediately on human victims and are continuously used for the next 24 hours then the effects of the toxin wear off with no lasting damage.

The life expectancy of a Blue-ringed octopus is only about two years because both the male and the female die after copulation. During copulation the male climbs onto the female’s back and inserts his hectocotylus, or modified arm, under the female’s mantle where he releases spermatophores into her oviduct. At this point the male octopus dies. The female octopus lays up to 100 eggs which she protects under her tentacles. These eggs hatch around 50 days later and are about the size of a pea. The female octopus is unable to eat while she is protecting her eggs and so dies soon after the eggs hatch. The young octopuses quickly grow into adults and begin mating the following year.

Blue Lined Octopus (a variety of blue ringed) Hapalochlaena fasciata

DAY OR REEF OCTOPUS (OCTOPUS CYANEA)

The Day octopus is also known as Cyane’s octopus or the Big blue octopus. As its name suggests it hunts during the day and so has developed an amazing ability to camouflage itself by rapidly changing the overall colour and texture of its skin. It has become adept at blending in so that it actually looks like the natural rocks surrounding it, both in colour and texture. Its complex brain can tell when it moves from sand to rocks for example and it immediately instructs the skin to change so as to resemble the new environment. The Day octopus is quite large with a body length of around 16cm and legs reaching 80cm but even this doesn’t stop them from becoming virtually invisible to predators.

Under normal circumstances the Day octopus has a brown colour with dark oval patches that resemble eyes. Occasionally however these false eyes are not visible.

The Day octopus feeds on crabs, small fishes, shrimp and bivalves. It excavates holes in coral reefs and these can be easily identified by the empty shells and other remains of its prey that litter the floor. The Day octopus is found throughout the Indo-Pacific region wherever there are coral reefs i.e. from the Red Sea to the areas around the Hawaiian Islands.

The Day octopus has a mating ritual that involves the male signalling his intent to the female by waving around his modified third right arm. He also darkens his skin colour and slowly approaches the female. If the female responds positively the male inseminates the female by releasing spermatophores into her oviduct. This is commonly done at arms length because the female has been known to eat the male after copulation. The female lays literally thousands of eggs and attaches them to the coral inside her lair. When the eggs hatch the youngsters feed on zooplankton until they mature into adults.

The Day octopus is not poisonous and is therefore fished in the areas mentioned above. As yet they are not reported to be under threat from extinction but if extensive fishing continues it is only a matter of time before they are.
TWO SPOTTED OCTOPUS (OCTOPUS BIMACULATUS)
The Two-spotted octopus has a pear-shaped body and can be commonly found in a variety of colours ranging from grey and dark brown to red, all with black patches. However this is slightly irrelevant as this species is capable of changing its colour very quickly should the need arise.

There are actually two separate species of the Two-spotted octopus but they are so closely related that they were thought to be one until 1949.

The first species can grow to around 30” or 76cm when the body plus arm length is measured. The arms are commonly around 4 times the length of the body and have alternating rows of suckers. They are arranged as four pairs with web in between. The octopus’s eyes are high on the sides of the head and have a distinctive black spot beneath each one. This species of Two-spotted octopuses can be found around the low-tide line up to about 50m in depth. They form lairs in crevices and natural caves beneath rocks.

The second species looks incredibly similar but has shorter arms that are only 2 ½ to 3 times longer than the body. It is found on the mudflats between the high and low-tide lines in addition to under rocks and in caves.

Both species are found around the coast of California and in the Gulf of California.

REEF OCTOPUS (OCTOPUS BRIARIUS)

The Reef octopus has a distinctive blue-green colour that becomes reflective under divers lights and this makes them very easy to see when they are out feeding on crustaceans, bivalves and small fishes in the coral reefs and seagrass at night. They are commonly found throughout the Bahamas and the Caribbean and are consequently known as Caribbean Reef octopuses.

Like other octopuses the Reef octopus can quickly change the colour of its skin to blend in with its surroundings. They have a body that grows up to 12cm in length and arms that can reach around 60cm.

The main difference between the males and females of the species is the presence of the modified arm in the male that functions as the reproductive organ. Fertilised females lay around 500 large eggs that normally hatch 50-80 days later. The young octopuses are very similar to the adults only smaller but they grow rapidly reaching 75% of adult size in only 17 weeks. They are able to move using jet-propulsion and release ink as soon as they hatch and reach maturity within 150 days.

Reef octopuses are solitary creatures and have been seen to show cannibalistic tendencies if kept in a group environment.

CARIBBEAN ARMSTRIPE OR BROWNSTRIPE OCTOPUS (OCTOPUS BURRYI)

The Caribbean Armstripe octopus is so called because of its distinctive brown stripe that runs the length of each arm. The overall colour varies but is commonly brown or grey.

This species has a self-protection mechanism that allows it to bury itself quickly in the sandy environment in which it lives.

ATLANTIC LONGARM OCTOPUS (OCTOPUS DEFILIPPI)

As the name suggests this species of octopus has incredibly long arms in relation to its body length. The arms are commonly around 30cm in length whereas the body is only about 6cm.

LONG-ARMED OCTOPUS (OCTOPUS MACROPUS)

The Long-armed octopus can commonly grow to about 36” or 1m in length when the body and arm lengths are measured. The arms are normally more than 7 times the length of the body, hence their name. They are quite distinctive with their red/brown colouring and small white spots however as with many other species they are able to change their colour whenever the need arises. They have eyes high up on the head with a distinctive bump above each one.

The Long-armed octopus can be found in the coral reefs of Australia, Malta and in the Florida Keys. They prefer rocky environments and so frequent the lower areas close to the sea floor. Here, they feed by night on a variety of crabs which they catch with the help of suckers on their arms. For self-defence they are able to release a dark ink that is thought to confuse any predators that present a danger.