Didymo spreads to Cobb Lake, Anatoki and Waingaro
Didymo, initially identified only in the Takaka River, is now present in the Anatoki River, the Upper Takaka River, and in the Cobb Lake, and recent samplings have confirmed the spread of the invasive algae into the Waingaro River, some 500 metres up from its confluence with the Takaka.
Ross Marley, a DOC ranger in Motueka, recently sampled all Golden Bay streams for didymo cells by setting up a driftnet and taking the benthic scrapings off the rocks, and confirmed the Waingaro findings, saying however: “Didymo was not yet visible in the Waingaro River. To me the water looked really clear but didymo may become visible eventually.”
All other waterways in the Bay are apparently still didymo free, including the Waikoropupu Springs. When testing the waters at the Springs, Ross took extra precautions.
“I was a bit scared of doing the testing in the Pupu and made sure my gumboots were really, really clean.”
Humans were definitely the number one distributors of didymo cells when entering waterways with contaminated gear for fishing, kayaking or swimming, Ross said. Waterfowl are believed to be unlikely to spread the alga, but shags have been blamed in the past for its spread as they lack water-repellent oil in their feathers.
Claire Webster has worked part time for DOC at the Waikoropupu Springs for the last two years. During her time as a “Springs Chick” or a “Pupu Cop” she has answered many visitor enquiries and has been impressed with “how many people care and want to do the right thing once they understand.”
“From the tourists we get questions like… ’Err, we have seen the signs and wondered is it a political group or a party drug?’ Or ‘Why can’t I stick my feet in the Springs to feel how cold it is?’ And I have to tell them that sandals like Tevas are very likely carriers as cells could happily sit down in the crevasses and seams in the damp for a few days, so stick your foot in the Springs and you have just introduced didymo.”
Because of the high contamination risk, the Springs will remain closed to all forms of contact including drink bottles, swimming, underwater photography and the immersion of body parts.
So far, 70 South Island rivers are known to be infected with didymo.
Ina Holst
