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Octopoda - North Pacific Giant Octopus
Topic Started: Aug 24 2014, 07:32 AM (2,884 Views)
Furka
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North Pacific Giant Octopus ~ Enteroctopus dofleini

Posted Image

General Information

Class: Cephalopoda
Order: Octopoda
Family: Octopodidae
Genus: Enteroctopus
Species: dofleini

Location and Habitat
Its spatial distribution includes the coastal North Pacific, along California, Oregon, Washington, BC, Alaska, Russia, northern Japan and Korea . 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.

Conservation Status
Posted Image

Sizes
Weight50 kg
Length (average)6 m
Height (average)<--->


In Zoos

Type of Exhibit: They live in pure seawater 33 – 36 ppt. – The temperature of the species range from 6 ºC - 11 ºC. There is
evidence that temperatures between 12 and 13 ºC are harmful over long periods. Octopuses are sensitive to metal concentrations particularly copper and tin (as are all molluscs). Many reports of octopuses escaping have been documented over the years since as a result it is common knowledge that an octopus aquarium needs a tightly fitting lid!
It is important to create as natural a habitat as possible within the aquarium- rock work should be built with an indent suitable for the octopus to use as a lair – this doesn’t necessarily need to be deep enough for the octopus to disappear from view completely but it should be deep enough for the octopus to feel secure. Artificial kelp is good for decorating the display and it is useful to use vertical theming such as floating ropes and buoys to break up open water spaces – this reduces the chances of the octopus picking up speed and jetting into the sides of the tank.
The size of giant Pacific octopus display is an important consideration – given a suitable quantity of food giant octopuses will rapidly grow to at least 2 meters arm span within 6 months of arrival as a 50cm juvenile. A cylindrical tank of 2m diameter and 2m depth at Blue Reef Aquarium Newquay seems to provide adequate space (6284 litres).The triangular shaped GPO tank at Seattle aquarium designed by Dr Roland Anderson has a total volume of 13,638l. Tanks with curved acrylic fronts have the advantage of deflecting a jetting octopus rather that stopping it dead and causing damage to its mantle tip.

Temperament: 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.
When working with giant Pacific octopus it is important to be careful not to allow the octopus to bring your hand or arm close to the beak – a bite from a giant Pacific octopus is very painful and can be very serious.

Diet: 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.
In captivity, they can be fed crabs or shell free raw sea food such as herring, smelt, squid, fish fillets, or clam meat.
Crabs are a more natural diet and are far less oily than most fin fish, but they leave remnants on the bottom which are visually unattractive and may contain bits of uneaten food, which may foul the tank.

Social Needs: GPO’s are loners and more than one should not be kept in an aquarium together. In the aquarium brittle stars and other sea stars are compatible. If you have sea stars in the tank they do a good job of cleaning up any left-overs from crab shells.
Fish have been used by some aquariums but the predatory nature of GPOs makes fish selection critical –only pelagic and active fish should be chosen and they must be species that won’thurt the octopus. Famously in one American aquarium a GPO was filmed eating its tank mate, a one metre long smooth hound shark!

Reproduction: 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. The female stores the spermatophore in her spermatheca until she is ready to fertilize her eggs.
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. 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. Hatchlings are about the size of a grain of rice, 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.

Extra Information:
  •  It is arguably the largest octopus species, based on a scientific record of a 71 kg (156 lb) individual weighed live. 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).
  • 3.3 million tons are commercially fished, worth 6 billion annually. Over thousands of years, humans have caught them via lures, spears, pot traps, nets and using only bare hands.
  • The giant Pacific octopus is considered to be long-lived compared to other species, with lifespans that average 3–5 years in the wild.
  • Octopuses are ranked as the most intelligent invertebrates. They have the ability to solve simple puzzles, open childproof bottles and use "tools".



Exhibit Examples


Extra Pictures
Edited by Furka, Sep 1 2014, 05:15 PM.
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