Blue bottle jellyfish have been making an appearance on the Papamoa beach this week, sparking an alert for swimmers.
The warmer temperatures are bringing the jellyfish to the area, which can leave people and dogs in pain if stung by them.
Also known as the Portuguese man o' war or the ‘floating terror', the jellyfish can leave people with stings and welts after tentacles have wrapped over the skin.
Despite its outward appearance, the Portuguese man o' war is not a jellyfish but a siphonophore, which, unlike jellyfish, is not a single multicellular organism, but a colonial organism made up of specialized individual animals (of the same species) called polyps.
These polyps are attached to one another and are unable to survive independently, having to work together and function like an individual animal.
The name ‘man o' war' comes from the man-of-war, an 18th-century armed sailing ship, and its supposed resemblance to the Portuguese version at full sail.
The Portuguese man o' war colony has a bilaterally symmetrical sail shaped bladder filled with gas, with tentacles at one end.
It is translucent, and is tinged blue, purple, pink, or mauve. The ‘sail' may be 9 to 30 cm long and may extend as much as 15 cm above the water. The gas bladder has up to 14 per cent carbon monoxide.
The remainder is nitrogen, oxygen, and argon—atmospheric gases that diffuse into the gas bladder. In the event of a surface attack, the sail can be deflated, allowing the organism to briefly submerge.
The stinging, venom-filled tentacles of the Portuguese man o' war can paralyze small fish and other prey.
Detached tentacles and dead specimens, including those that wash up on shore, can sting just as painfully as the live organism in the water and may remain potent for hours or even days after the death of the organism or the detachment of the tentacle.
Stings usually cause severe pain to humans, leaving whip-like, red welts on the skin that normally last two or three days after the initial sting, though the pain should subside after about 1 to 3 hours, depending on the biology of the person stung.
However, the venom can travel to the lymph nodes and may cause symptoms that mimic an allergic reaction including swelling of the larynx, airway blockage, cardiac distress, and an inability to breathe.
Vinegar applied to the stings is not recommended, as this can make the blue bottle stings more painful. Instead, washing the affected area with saltwater, removing any tentacles or sting attached to the skin without touching them, and then placed the affected skin in warm water -45 degree Celsius - is encouraged.
Relief can also be experienced by the application of shaving cream to the wound for 30 seconds, followed by shaving the area with a razor and rinsing the razor thoroughly between each stroke. This removes any remaining unfired nematocysts which hold the stinging venon.
After this, heat in the form of hot salt water or hot packs may be applied, as heat speeds the breakdown of the toxins already in the skin.
If the reaction is severe or symptoms worsen, antihistamines and hydrocortisone creams may help.
If a person develops reduced consciousness or difficulty breathing call 111.