9 December 2005
Toxic Algae Bloom
“Warm weather and low river levels have created ideal conditions for the growth of toxic algae in some watercourses”,
says Greater Wellington Pollution Control Officer Howard Markland.
“Toxic algae have been found in the Mangaroa River catchment and in the Hutt River downstream of its confluence with the
Mangaroa River. We have checked the Pakuratahi River (at Kaitoke Regional Park) and not found evidence of the algal mats
that are problematic in the Mangaroa River and lower parts of the Hutt River.
However, as a precautionary measure, Territorial Authorities and the Regional Public Health service consider the entire
Hutt River catchment to be potentially affected.
“We are not concerned about the usual bright green algal growth in streams as this is non-toxic. It’s the heavy, thick
growth of brown, grey and dark green algal mats that is the problem.
Howard says it looks like we are in for a long hot summer, and so this may be a recurring problem for some streams,
lakes and rivers. “While the Kaitoke Regional Park waterways do not appear to be affected at the moment, the public
should check with Park Ranger Steve Edwards after a spell of dry warm weather, and tell him about any sightings of
unusual or dense algal growths.”
He says Regional Public Health, in consultation with City and District Councils will decide when to lift river
restrictions and remove warning signs.
“If anyone has concerns regarding the risk to their pets’ health they should seek advice from their vet. Likewise, if
you experience symptoms such as skin or eye irritation, or stomach upset after being in contact with affected waters,
contact your doctor. As a precaution all dogs should be kept on a leash until the catchment is declared safe.”