Canterbury beach covered in bluebottle jellyfish
Warmer water temperatures have brought "hundreds" of harmful bluebottle jellyfish to some of Canterbury's beaches this summer.
Surf Life Saving New Zealand reported earlier this month that bluebottle jellyfish stings had accounted for a third of the first aid actions its lifeguards had carried out this season.
The bluebottles have been sighted all along the Canterbury coastline this season, with a line of the jellyfish often appearing on the sand at the high-tide mark and some floating around in the shallows.
Kaiapoi resident Andrew Loo saw "hundreds" of jellyfish littering the Waimakariri River mouth near Kairaki on Wednesday evening.
"I went down to the beach with my son in the evening. I was quite surprised - [the jellyfish were] all over the place, all over the beaches."
The jellyfish had a "small and purplish" appearance and Loo recognised them as something that had given him a "nasty sting" in the past.
The jellyfish were "in the sand" and in the water, he said.
"Because there's so many . . . we decided to leave; it was just too dangerous."
Loo has lived in the area for more than 10 years but this was the first time he had seen bluebottle jellyfish at Kairaki.
A Canterbury District Health Board spokeswoman said one person had alerted health authorities to the jellyfish in the region.
Summer was a common time for jellyfish to appear along the coastline because water temperatures were warmer, she said.
No fatalities have ever been reported in Australia or New Zealand from the sting of a bluebottle jellyfish (also known as the Portuguese man-of-war).
The bluebottle is not a true jellyfish but does have a burning sting.
Symptoms can include swelling around the lips and eyes, severe dizziness or faints, persistent sneezing or coughing, chest tightness, rapid development of a rash and signs of shock.
Anyone stung by a bluebottle should immerse the stung area in warm water (about 45 degrees Celsius) for 20 minutes.
Stings from other types of jellyfish should have warm sea water poured over them, or vinegar - but vinegar should not be used for bluebottle stings.
Fresh water should not be used on stings either, as that could activate the stingers.
Anyone who experienced increasing numbness or difficulty breathing, or showed signs of poisoning or later infection, should see their doctor.
- The Press