Estuaries among the worst in NZ
TODAY’S SHIPPING
Estuaries in the Marlborough Sounds are among the muddiest in the country, a new report shows.
The Wriggle Coastal Management report on the Kaiuma Estuary, in the Pelorus Sound, was presented to councillors at an meeting on Thursday.
The report shows 72 per cent of the intertidal area of the estuary is covered in soft mud, which reduces the habitat for shellfish, birds and plants living in the area.
Another report on the Mahakipawa Estuary, also in Pelorus Sound, showed a similar trend, with about 62 per cent of the intertidal area covered in mud.
SLR Consulting scientist Reid Forrest said seagrass was completely absent at the two main study sites in the estuary, and there was a low diversity of epifauna (animals living on the surface).
’’[The amount of mud] really puts it up there with some of the worst estuaries we’re seeing around New Zealand,’’ he said.
Environment committee deputy chairman Gerald Hope said the reports made it clear there had to be a change in values and practices in the catchment areas feeding into Pelorous Sound.
‘‘This is incremental change, it’s man-made,’’ he said. ‘‘The reports we’ve had over the years are evident: we have to change our land use practices because increasing sedimentation is going to be irreversible unless we act now.’’
Leigh Stevens, who produced the Kaiuma report, said while other indicators for the estuary’s health were good, the enormous amount of mud was concerning.
‘‘Once you get above 15 per cent mud in an estuary you start to see problems - so we’re very, very high in terms of the national picture,’’ Stevens said.
Previous studies by environmental consultant Rob Davidson, in 2005 and 2015, indicated there had been a significant increase in the amount of mud since 2012.
But tracking the source was more difficult.
Buffalo, 6,311 tons, berth only, LU1; Toll Transfer, berth only, Abel; San Hauraki, 243 tons, repairs only, KQE; Eagle, 1,355 tons, unload fish, Amatal; Pelican, 942 tons, berth only, CR; Moon Shadow II, 160 tons, repairs only, Slip Jetty; Titirangi, 137 tons, repairs only, LU2; Seaworker, 344 tons, Equi; Tia Marta, 21,532 tons, load logs, KQ; Aleksey Slobochikov, 4,407 tons, unload fish, load bunkers, LU1; Amaltal Mariner, 555 tons, unload fish, Amatal. Expected: Johannes Maersk, 30,166 tons, containers, MWS, today; Passat Summer, 32,200 tons, containers, MWS, today; Firmament Ace, 60,118 tons, unload vehicles, MWS, today; Spirit of Canterbury, 9,910 tons, containers, BQ, Tuesday; Seatrade Blue, 24,905 tons, containers, BQ, Tuesday; Trans Future 6, 60,414 tons, unload vehicles, load processed forestry, MWS, Wednesday; ANL Elanora, 18,327 tons, containers, BQ, Thursday; Meridian 1, 4,407 tons, unload fish, load bunkers, LU1, Thursday.