Waikanae estuary degraded
Waikanae Estuary Scientific Reserve, promoted internationally as a showcase for marine and bird life, is being degraded, according to an unpublicised report commissioned by Greater Wellington Regional Council.
Far from being “pristine” for the environmental and ecological values claimed by the Department of Conservation, the reserve’s condition only rates as “moderate”, with serious adverse effects reported for fish spawning and bird habitat.
The three-year-old report came to light during research by the recently-formed Waikanae Estuary Whitebaiters Network into unsubstantiated claims by DOC that whitebaiter vehicles on the beach harm shellfish, bird life, and people.
Network spokesmen Rakauotearoa Te Maipi and Chris Turver say a broad scale habitat mapping report by scientists Leigh Stevens and Barry Robertson shows Waikanae estuary in only a moderate state due to habitat loss, smothering siltation, excessive nutrients from runoff and disease risk.
The causes singled out include residential development around the perimeter and associated drainage, flood and erosion protection measures, drainage of wetland areas, channelisation of streams, and the cutting of tidal flows to the northern end of the reserve arm of the estuary which “significantly adversely impacts on native fish spawning and bird habitat”.
The Department of Conservation is responsible for managing the scientific reserve, the Ka¯ piti Coast District Council for residential development and drainage, and Greater Wellington Regional Council for flood and erosion protection.
The report says based on the current level of sediment deposit the upper estuary is expected to infill rapidly and become muddier and less diverse.
The report’s conclusion is that “such conditions limit food availability for fish and birdlife and show the ability of the estuary to assimilate sediment loads is currently exceeded”.
The Whitebait Network spokesmen say the degradation of the estuary is an indictment on the management of the reserve and makes the movement of whitebaiter vehicles on the beach pale into insignificance.
“It’s not whitebaiters who cause problems but significant modifications to the estuary by the very agencies which are charged with protecting the environment.”
They say many thousands of people, including whitebaiters, have been led to believe DOC publicity that the scientific reserve is an international showcase for conservation and environmental values and must be protected at all costs.
“In reality it appears it is being allowed to smother and die through inaction by the authorities.”
The spokesmen have called on Conservation Minister Eugenie Sage to investigate how her department has allowed the reported level of degradation to occur and to withdraw the designation of “scientific reserve” until it justifies the title.
They say but for the valiant efforts of unpaid local environmental care groups the reserve would be in a worse condition.
Department of Conservation Ka¯ piti Wellington operations manager Jack Mace responds:
The report mentioned by Mr Turver confirms that Waikanae Estuary is a nationally significant wetland habitat — one of very few in the southwestern North Island. More than 60 species of birds breed there, and more wild birds visit it than any other area in the Wellington region.
Development since the 1960s has transformed land around the estuary from coastal wilderness to suburbs.
In the 1970s the Waimeha swamp was drained and whitebait spawning grounds were lost.
Waikanae Estuary Scientific Reserve was established in 1987, with the help of concerned locals, to protect the remaining area. Previous degradation can’t be undone, but we can and will protect what’s left.
Threats to the delicate coastal environment — and to people’s enjoyment of it — do include vehicles on beaches.
“That activity is illegal. DOC works with dedicated local volunteers on weeding and restoration planting in the reserve, which shows how local people value this place.
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