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Aquatic: Blue Button (Porpita pacifica)

Find, identify & discuss the insects of SANParks
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Junior Virtual Ranger
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Joined: Sun Feb 13, 2005 9:42 am
Location: Ballito, KZN, RSA

Aquatic: Blue Button (Porpita pacifica)

Unread post by Klystron » Mon May 01, 2006 2:52 pm

Elsa and I found this little creature in a rock pool at Port Edward and would be interested to know what it is. Unfortunately my son had my big camera and this is with a phone camera (usefull in such emergencies).

The body is about the same size as a RSA R1-00 coin and the legs about 2 to 3 cm long.

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Joined: Thu Dec 29, 2005 11:54 am

Unread post by Seahorse » Wed May 03, 2006 11:15 pm

Thanks for the interesting photograph ! Cellphone is king.

Your little animal is one of my most "favourite" animals.
I love the sea and have been diving from an early age.
There is nothing that spoils a nice day's diving as successfully as a a little floating fireball against your skin.
Their name is Porpita pacifica or in real language, a raft hydroid.
The lovely blue fringe around the edge is in fact a ring of stinging tentacles. It is these electric blue tentacles that supplies a really nasty sting to the unwary swimmer.
Some people are more sensitive to their venom than others, but it is unpleasant at best.
Porpita belongs to the class Hydrozoa.This group contains the Bluebottles and other floating "nasties" that sting humans when they enter the sea.
The stinging tentacles were surely not designed just to be nasty to humans. In fact ,the stingers are actually a most sophisticated way of capturing their food.
One shot of one of these stinging cells (some look just like miniature harpoons)will be sufficient to subdue a planktonic prey animal sufficiently to enable the organism to feed on it.
If they sting a huge human so badly, you can imagine what happens in the microscopic realm of plankton.
Do yourself a favour and read more about these fascinating creatures. They are beautiful to look at and getting to know you can save your life one day.
There are many pieces of advice about the treatment for stings from these little chaps, but I find ordinary vinegar is very effective to neutralise the stings.
Remember to keep anti-histamine tablets and cream in your first-aid kit when you go to the beach.Anti-histamines counter the body's reaction to the foreign protein contained in the hydroid venom
Any sign of unusual reaction to the sting should be taken to a medical practitioner right away !
Do not allow this information to scare you away from the beach. Go there, get some sand in your pants, and live a little !
THE SEA IS A GRRREAT Place to be !
Peet Joubert
Park Manager (Knysna)

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Junior Virtual Ranger
Junior Virtual Ranger
Posts: 54
Joined: Sun Feb 13, 2005 9:42 am
Location: Ballito, KZN, RSA

Unread post by Klystron » Thu May 04, 2006 5:52 pm

Many thanks for a most interesting reply. Elsa tells me she nearly scooped it up in her hands but the colour being so close to a blue bottle stopped her. A piece of flat plastic was floating nearby and she used that instead. The Cellphone pics that I took while it was on the plastic turned out to be very out of focus so I did not post any of them. We released the creature and I took two more before the current carried it away. Thanks again.

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