Recording old oceans centre tag.
Wave rider buoy 'very valuable'
Since 1995, NIWA’s wave rider buoy off Baring Head, near the entrance to Wellington Harbour, has been providing the harbourmaster, Toll NZ (formerly Tranz Rail), and the MetService with accurate measurements of the waves off Wellington’s south coast.
Captain Mike Pryce is the Wellington regional harbourmaster.
Offshore exploration
This shows the modelled mean currents off the east coast of the North Island. The colours show the speed of the currents. The arrows show both direction and speed (the longer the arrow, the faster the current).
The main feature is the East Cape Current which flows down the east coast and turns off eastward near 42° S (south of the Wairarapa coast). Here it joins current from Cook Strait giving the strongest mean currents of over 30 centimetres per second (shown in red).
Habitat mapping highlight
The demonstration on Tangaroa included imaging this wreck of a minesweeper which sank in Wellington Harbour in 1942 after colliding with an inter-island ferry.
Ian Wright (below right), national centre leader, and Kevin Mackay, marine data manager, demonstrating seabed mapping on RV Tangaroa.
It sounds easy, but equipment and vessel time as well as unpredictable weather make it time consuming and expensive to map the seafloor using cameras alone.
At NIWA, we have developed a quicker, more cost effective method. First we acoustically map the seafloor using technology such as sidescan or multibeam sonar. We use the acoustic images, and our ecological experience, to guide where we deploy video cameras. Once we have the video footage, we use statistical techniques and ecological information on the importance of various species to classify the observations into habitat types.
NIWA has been designing and analysing long-term monitoring programmes for the Auckland Regional Council (ARC) to check whether the ecology of some of the region’s harbours is changing.
It can be difficult to measure the impact of human-induced changes on the animals which live in the sandflats, mudflats, rock, beaches, and other terrain between the high and low tide marks. The creatures are generally small, hidden, and tend to cluster together in small patches.
