Algae risk for dogs and small children
High amounts of toxic algae in the Maitai could harm dogs and small children, warns a Cawthron scientist.
Cawthron Institute senior scientist Dr Susie Wood said she had found toxic algae, also known as Phormidium, in several places along the Nelson river, particularly downstream of the campground.
She said her attention was drawn to the blooms when a colleague mentioned her dog had eaten the toxic algae on a walk on Sunday evening.
‘‘The dog is actually OK which is good but she was in a bit of a panic.’’
Wood said while of little risk to adults, dogs and small children could still be at risk from the algae.
The national river toxic algae guidelines say that at 20 per cent toxic algae coverage in a river, council starts monitoring more often and at 50 per cent coverage health warnings are issued.
Exposure to the dark-coloured algae found on rocks and riverbanks can cause vomiting, diarrhoea and abdominal pain in humans, and is potentially deadly to dogs and stock when ingested in large amounts due to the neurotoxin it produces.
Wood said her colleague had found the algae floating on the side of the Sunday Hole swimming hole, in the Maitai River.
‘‘Typically they don’t grow in pools but they’re growing upstream and as they detach they float down and they accumulate on the edge of these pools,’’ Wood said.
‘‘If anything that’s the biggest thing we should worry about, when we’ve got them accumulate in pools because that’s where all the kids are playing and swimming.’’
Wood ‘‘strongly’’ suggested dog owners find a different place to walk their dogs and to inform themselves of what toxic algae looks like.
‘‘The beach is a good place and of course there are many safe rivers around the Nelson region.
‘‘Council can’t monitor all of those rivers so don’t rely on there being [warning] signs.’’
Wood said she had also seen toxic algae blooms in the Wai-iti River in Tasman. She said blooms were expected to be around in the Nelson and Tasman rivers until at least March or April.
Tasman District Council communications adviser Chris Choat said at all times of the year people should be aware of what the toxic algae looks like, especially dog owners who take their dog to the rivers.
‘‘The presence of toxic algae is growing with coverage is getting up to about 15 per cent in the Waiiti and a bit less in the Waimea.
‘‘This level of coverage is currently below guidelines so we have not put out warnings.’’
Nelson City Council monitors the Maitai regularly and their last reading from January 4 shows the levels of toxic algae were low.
The reading comes out every Wednesday.