NIWA scientists have been scanning the Hawke’s Bay seabed to measure Cyclone Gabrellie's effects.
Metres of silt and mud are smothering reefs and killing ecosystems on the Hawke’s Bay seabed following Cyclone Gabrielle.
Using a shallow water sonar system to create a 3D model of the sea floor, National Institute of Water and Atmospheric Research (NIWA) scientists have been mapping the seabed for weeks to help understand the effects of Cyclone Gabrellie.
The system sends out an acoustic pulse that echoes off the sea floor to determine the depth and relative hardness of the area.
NIWA scientist Joshu Mountjoy said huge amounts of silt came down local rivers and into the ocean after the cyclone.
“On land, on the flood plains here you can see a metre or more of silt has been sitting around in some places and much more than that has been left on land will have been taken into the ocean,” Mountjoy said.
It follows the damage caused by Cyclone Gabrielle. (Source: 1News)
There are now concerns about what the silt is doing to marine ecosystems.
“The animals living on the reef have been completely buried beneath a meter of mud for example that can completely smother them and that is not their habitat they’re filter feeders they’re filtering the ocean so that could kill them off completely,” Mountjoy said.
Commercial fishermen are now traveling hours down the coast to avoid the silt and debris.
Local fisherman Kar Warr said he's fished in East Coast waters for decades and has never seen it this bad.
“Nets are going with holes in them, you never know what state they will be in when you pull them back up, it’s been a fair bit of heartbreak and anxiety,”
“With the softer sediment, the gear will want to sink into it, the sensation on the boat feels like you have run into an obstacle,” Warr said.
“It is very hazardous it could cause boats to sink if anchors get stuck in mud and debris while big waves come, people need real caution when throwing anything over the side of boat anchors, cray pots,” Warr said.
NIWA's full report will be published in the coming months, to give a better understanding of the damage.
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