August 2005
The Portuguese Man-of-War
Order
Family
Genus and Species
Hydrozoa
Siphonophora
Physalia physalis
This peculiar looking sea creature is found in the warm
waters of the Atlantic, although sea
currents and winds sometimes drive them towards land. This is
when they are especially
dangerous to swimmers and surfers. They got their name because
they resemble the helmet
worn by early Portuguese conquistadors.
They are a pinkish-purple or blue color and
on a
still ocean, they can be seen for some distances because of their shiny,
translucent float.
They stay afloat through the use of a gas-filled
bag ( notice the illustration above), and have
long tentacles which sometimes reach 180 to 190 feet long. These
tentacles contain numerous
tiny hairs which are hollow and
which secrete a poison that paralyzes and
kills their prey
which normally consist of small fish, crustaceans,
fish larvae and plankton. These small sea
creatures only need brush lightly against the tentacles for them to
pop open, inject their poison,
and begin the digestion process. One of the only fish which is
apparently not affected by this
poison is a small fish called Nomeus.
They may be found swimming through the tentacles,
searching for small tidbits of food.
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Above is a highly magnified picture of the tentacles
with their thousands of tiny hollow hairs
which actually draw small sea creatures into the tentacles where they
are killed and eaten.
The poison released by the tentacles is not often
fatal to man (except for the unlucky few who
have severe allergic reactions to the
venom) but does create painful blisters and lesions in most
people, which does require immediate medical
care to relieve the pain and to heal properly.
Many unfortunate swimmers have encountered schools of these creatures
and have regretted
their misfortune greatly.
The Man-of-War (also known as a bluebottle) is not one creature,
as it is commonly
assumed, but a complete colony of numerous polyps...each
performing their own functions.
There are polyps which do nothing but digest the captured food and
distribute nutrients to
polyps which are not capable of digestion on their own. There
are polyps which produce
the Medusa, a disc shaped organism
which produces eggs and sperm. This
organism breaks
away from the main Portuguese Man-of-War and floats off to produce
many more polyps
which, in turn, gather together to form another complete creature.
There could be hundreds
of polyps which make up the creature we know
as the Portuguese Man-of-War.
The weight of the Portuguese Man-of-War varies since all these organisms
are different
and are made up mostly of water. The float
may grow up to 13 inches with the trailing
tentacles sometimes reaching 190 feet in
length. They breed all year long and
produce
several million polyps during their lifetime. The birth
interval is continuous and it is not
know for sure how long they live. They belong to the Hydrozoa
order which contains
over 2500 species which include corals,
jellyfish and sea anemones.
I would be remiss in the study of this creature if I did not include
first aid tips to follow
if you are ever stung by a Portuguese Man-of-War.:
1. Leave the
water immediately.
2. Gently
remove any part of the tentacle which is sticking to the skin. (Use tweezers...
never brush or try to rub
the area with your hands or any other object. This will
often break the skin, allowing
more venom into the body.)
3. Ice and
sprays which numb the skin will often benefit less serious stings.
4. More serious
stings will require immediate medical attention.
As far as being threatened with extinction, the Portuguese
Man-of-War is not in any such
danger. They are susceptible to
oil spills and are sometimes blown ashore by strong winds
but they reproduce at such phenomenal rates that it
would take an ocean-wide disaster to
wipe out the species.
Shown below (shaded in blue) is the area of the world where the Portuguese
Man-of-War
is found.
Be sure to check back next month for September's "Creature of the Month" The Anaconda.