Good news – a big increase in cockle numbers has shown up in the latest survey by Guardians of the Pauatahanui Inlet (GOPI). This signals that the intent of Porirua’s Harbour and Catchment Strategy (2012) is being realised, with a rise in cockle count a pretty good indication that the health of our beautiful harbour and estuary is being restored.

Numbers have risen from 277 million to 336 million since the last survey in 2010. That’s 21 per cent more cockles, at a time when some parts of the country are experiencing staggering losses in shellfish numbers. Back in 1995, when increasing sedimentation and contamination with heavy metals, and toxic levels of phosphorous and nitrogen, were only just being formally acknowledged as seriously affecting the inlet and its ecosystem, cockle numbers were a massive 87 per cent fewer – so we could be doing something right.

New Zealand flax flourishes at the shores of Pauatahanui Inlet – this is one of our most distinctive native plants. Its sword-shaped leaves grow in a fan shape and in spring, birds – particularly tūī – flock to feed on the nectar of its tube-like flowers, blooming on stems up to 4.5 metres long. New Zealand flax is related to the day lily. Growing naturally only in New Zealand and Norfolk Island – no other country has produced a plant quite like it. There are two confirmed species in New Zealand: Phormium tenax and Phormium cookianum. The more common Phormium tenax, with its distinctive red flowers and upward curving seed pods, is also known as harakeke or swamp flax. Thanks Teara.govt.org.nz for this information. Image R M Moore

GOPI representative, Professor John Wells, praises the efforts of Greater Wellington Regional Council, Porirua City Council, farmers and urban developers, for drastically reducing the amount of sediment entering the inlet, which is “undoubtedly having a positive effect.” High praise must also go to GOPI volunteers, for the amazing work they do in raising awareness around the importance of treating our inlet, harbour and wider catchment with respect. GOPI has been looking after the interests of Porirua’s prized toenga (treasure) for more than 20 years now – promoting activities like the cockle count, rubbish clearing, planting, and an annual photo competition – really making a difference.

GPOI undertake their cockle survey every three years, with NIWA (National Institute of Water and Atmospheric Research) doing the analysis. View NIWA’s report and other details about Pauatahanui Inlet on GOPI’s website http://gopi.org.nz.

Here are some things  happening as part of the Poriruia Harbour Strategy and Action Plan – thanks Porirua City Council – for more details, see their website:

• Sewer and stormwater upgrades. This is underway, with $20M earmarked over 10 years, to improve degraded sewer and stormwater networks.
• Porirua Stream-mouth Enhancement Plan – being developed by a consultant with local community groups.
• Catchment Sediment Reduction Plan. Research has been completed to identify the critical areas where sediment and erosion stabilisation is essential. This data has enabled development of a prioritised sediment-reduction plan for the whole catchment. Councils will develop programmes to implement the plan, including identifying opportunities for community participation.
• Fish Survey. Ngāti Toa Rangatira and NIWA have completed an oral history, and review of the relevant literature and are proceeding with the third and fourth stages including a harbour-wide fish survey and a shellfish survey of the Onepoto Arm to complement the existing triannual Pauatahanui Cockle Count. The survey and cockle count will give us a baseline from which to gauge biological trends in the harbour as the Strategy is implemented, to guide aspects of the estuary restoration.