Essay/Term paper: Life of octopus dofleini

Essay, term paper, research paper:  Science Reports

Life of Octopus Dofleini


Introduction

This is a research report on octopuses in general, however will focus in
on a particular species of octopus, the North Pacific Giant or octopus dofleini ,
which is a bottom dwelling octopus that lives on coasts of the pacific ocean,
from California to north Japan. This report will cover the habitat, and
lifestyle of this amazing mollusk, that is so often misunderstood. The octopus
is a very intelligent, and resourceful invertebrate whose natural abilities
should make this a fairly interesting reading.

REPRODUCTION OF O. DOFLEINI

The spawning of the giant pacific may occur at any time of the year,
however the mating of the octopus peaks in the winter months, with the peak of
egg laying in April and may. Octopuses reproduce sexually, and have both male
and female octopuses. Reproduction takes place as follows: The male octopus
uses his tentacle to take a mass of spermatophore from within his mantle cavity,
he then inserts it into the oviduct, in the mantle cavity of the female. This
process occurs at depths from 20-100m and, lasts hours. With female octopuses
receiving spermatophore up to 1m long.
Female octopus seem to prefer larger males as mates and male octopus may
mate with more than one female in their life span, however the male octopus only
lives a few months after breeding, and the female will die shortly after the
eggs hatch.
Incubation can take from 150 days to seven or more months. The female
may produce any where from 20,000 to 100,000 eggs over a period of several days.
During incubation the female octopus will take to cleaning and aerating the eggs.
This takes place at a depth of less than 50 meters

LIFE SPAN OF O.DOFLEINI

After hatching, the baby octopus (or larvae) take on the role of
plankton, drifting around the ocean feeding on neuston (dead food) as opposed to
hunting live prey. This stage on an average lasts for 30-90 days.
Without mating the octopus may survive up to five years, and Giant
Pacific octopus have been found to reach a weight of 600 pounds, and an
estimated width of over 31 feet, But the average size is only 100 pounds and 3m,
still weighing in as the largest species of octopus.
During their life span, many octopus fall victim to fatal, and non-fatal
predation. Therefore a high percentage of octopus are mutilated or missing arms,
this percentage increases in octopus that live in deep water, perhaps this is
because older octopus tend to occupy deeper waters and would naturally have more
battle scars. However larger octopus are less prone to these injuries. Among
the predators of octopus are, other octopus, sea otters, seals, sea lions, and
fish.
THE DEN OF THE OCTOPUS

In finding a den an octopus is a very resourceful animal. Although most
octopuses prefer to make natural rock crevices, and underground caves their dens
smaller octopus tend to excavate areas of sea floor to build their own den, and
still other octopuses prefer to occupy man made dens, such as ship wrecks.
Although the octopus is not territorial, and may only occupy a particular den
for a few weeks at a time, the den seems to be a important aspect of the
octopuses life. The octopus uses its den for hatching its eggs, feeding, and
even retreats to its den to hide from predators such as other octopuses, and
seals. A common site marking the entrance to an octopuses den is a pile of
shells, and other refuge discarded after feeding. Although dens are an
important place to the octopus, octopuses are very mobile animals.
FEEDING HABITS OF THE OCTOPUS

Octopuses feed on everything from smaller octopus, to crustaceans, but a
favorite food appears to be crab, and shrimp. As a general rule octopuses hunt
prey during hours of darkness, and retreat to their den to feed. Many octopus
over take prey with use of venom of varying strengths, while others simply
capture prey and consume them with their bird like beak.
LIFESTYLE AND PHYSICAL ATTRIBUTES OF OCTOPUS

As in other aspects of the octopuses life, it is very resourceful, and
interesting in its defenses and hunting techniques. Some species of octopus,
such as the Blue ringed variety (Hapalochlaena lunulata) Are deadly poisonous to
man. This octopus can administer its poison in two ways, it can either bite
with its bird like beak, or release its poison into the water surrounding its
prey. This poison attacks the nervous, and respiratory systems of man, causing
death in roughly one hour. There is no known anti-venom, so the only way to
survive an attack is through the administration of CPR until the poison wears
off in several hours. It should be noted that the primary use of this poison is
in hunting prey, not defense.
Octopus have the ability to change their skin coloration (like a
chameleon) in order to camouflage themselves. This is accomplished through
action of the chromatophore cells in the skin. Chromatophore cells are made up
of three bags containing different colors. These colors are adjusted until the
background color is matched. The normal color of the North Pacific Giant is
brown, however the octopus can change color according to mood, Red representing
anger, white representing fear, and surely there are more moods with colors to
match which are more subtle. This ability to change color according to mood was
for several years doubted by the scientific community, but is today a common
belief.
The skin of the octopus is of varying softness, but all octopuses have
very soft bodies. In fact the only hard part of the octopuses body is the beak,
this allows octopuses to fit through holes no larger than the beak its self.
All octopus have the ability to shoot out a jet of purple, to black inky
fluid from under their eyes, in order to perform a disappearing act when they
feel threatened. The octopus can shoot out several blotches of this fluid
before the fluid sac is emptied. This trick is not always an option, the ink is
actually toxic to the octopus, and if shot in a confined area, the octopus will
become sick or even die.
Octopuses have fairly good eyes, in fact they are comparable to ours in
clarity. The eyes of the octopus differ from ours, in the respect that they
focus by moving in, and out. Whereas the human eye focuses by changing the
shape of the lens its self.
The octopus posses the most advanced brain of all invertebrates, with
both short, and long term memories. This allows the octopus to learn in much
the same way as humans, through trial and error. When an octopus learns a
lesson it remembers and puts its knowledge to use in the future. The
octopus has eight arms, with 250 suckers on each arm for a total of 2000 suckers
on their body. These suckers are very sensitive to touch, in fact, the octopus
can differentiate between different objects just as well with their suckers as
they can with their eyes. Some species have particular suckers that are larger
than the rest, This is to aid in reproduction. Although octopuses often lose
arms to predators, it is of no consequence as the arm will grow back in a short
time.
The Pacific Giant Octopus is of the phylum mollusca, class cephalopod,
order octopoda, family octopodidae, and their closest relatives are the
chambered nautilus, squid, and cuttle fish. The squid is in many ways similar
to the octopus. The squid (like the octopus) changes skin color according to
mood and background, and The feeding activities of the planktonic O. dofleini
are described as squid like darting.
THE MIGRATORY HABITS OF O. DOFLEINI

The medium to large pacific giant is believed to go through a migratory
stage in which it migrates from shallow to deep water and back again, the
migratory cycle runs as follows: shallow water October-November/deep water
February-March/shallow water April-May/deep water August-September.
O. DOFLEINI AND MAN

The pacific giant is the most common commercial species of octopus and
is caught by fisheries from north Japan to Washington state. The octopuses are
caught in large sometimes clay pots and raised to the surface. The octopuses
are used for bait and for consumption by humans. Although these octopuses are
caught in nearly all of their habitats, they are not endangered.
The ocean is where life began, and is a far more competitive, and
harsher world than the world we know. So it comes as no surprise that the most
advanced and well adapted life forms would be found in the ocean. Although
octopuses do not build large structured civilizations, they are obviously
another form of intelligent and highly adapted life forms.