Waka trawls for plastic in coastal waters
A waka conducting New Zealand’s first plastic trawl has found microplastics are accumulating in the waters around Kiwi shores.
The Te Matau a Ma¯ ui pulled up plastics during its voyage from Napier, reaching as far as Cape Palliser, as part of the Waka Odyssey before being turned back by the stormy conditions created by ex-cyclone Gita.
Waka captain Raihania Tipuki believed the trawl was the first of its kind conducted in New Zealand waters, and a second waka, Hinemoana, was to complete the research in Wellington Harbour on Tuesday.
‘‘Off the Wairarapa coast we were getting one or two pieces per trawl. Once we got into the harbour at Hawke’s Bay, that’s when you started to see a lot more.’’
Roughly 18 pieces of plastic were captured during one trawl of Hawke’s Bay harbour, and that did not include nano plastics, which would be counted from samples in a laboratory.
‘‘That’s just a tiny part, if you imagine how much is floating around Hawke’s Bay.’’
The findings were dwarfed by what the team found on Wellington’s Oriental Beach.
In three 1-metre transects the team found 230 macro plastics, 146 micro plastics, and 2412 nurdles – an industrial plastic waste that can carry concentrated levels of toxins that enter the marine food chain. ‘‘The nurdle count here is higher than any other beach that our international researchers have seen,’’ Tipuki said.
Speaking before the weekend’s beach survey, Tipuki said one of the researchers on the waka had their own blood tested, and found it contained chemicals contained in plastics.
‘‘The trawl itself is a piece of metal, 600cm wide by about half a foot tall. It’s like a funnel, and the net’s attached to that,’’ he said.
‘‘You’re dragging it through the water for an hour at three knots, so it’s only a small transect of the water that it’s dragged through, but it picks up anything that’s floating.’’
Tipuki said the lack of research into the prevalence and effect of plastics on New Zealand coastlines illustrated how far Kiwis still had to go in dealing with the plastic issue. ‘‘We need to be more forward thinking about all environmental issues.’’
The Waka Odyssey, which concluded with a ceremony on Wellington’s waterfront with the arrival of four double-hulled waka and roughly 30 smaller canoes as a part of the New Zealand Festival, provided an excellent opportunity to draw attention to a growing issue.
Last year American researchers mapped the edges of a 2.5 million square-kilometre plastic patch, around Easter Island and Robinson Crusoe Island.
On Tuesday a 60,000-signature strong petition will be handed to the Government, along with a letter calling for action against single-use plastic bags – a major contributor to ocean plastics.
This will be followed by the Oceans in Peril panel discussion on Wednesday, which is being conducted as part of the New Zealand Festival.