Tsunami mauls mussel farms
Tsunami currents caused by the massive earthquake in Japan snapped anchor ropes on marine farms in the Marlborough Sounds, tangled mussel lines and damaged mussels ready for harvest, marine farmers say.
The damage could tally up to hundreds of thousands of dollars.
Farmers in Port Underwood and Croisilles Harbour have been worst affected, with more than 100 lines damaged by strong, erratic currents caused by the magnitude 9 earthquake off the east coast of Japan on Friday.
Repairs may take up to 10 days.
Port Underwood mussel farmer Bruce Hearn said he watched as strong currents surged into the area from about 3pm on Saturday until about 2pm on Sunday.
"The tide was running in and out several metres and I knew exactly what was going to happen. I was watching whole lines move around in enormous forces.
"Parts of it [the sea] looked like the entrance to Tory Channel when the tide is running. The water was sort of boiling.
"It looked a bit like a washing machine with currents coming from all sorts of angles. The currents are so strong they take silt off the bottom."
About 70 mussel lines were damaged, including 15 of his own, Mr Hearn said.
The eastern arm of Port Underwood and nearby Kaikoura Bay were worst hit and the area was still getting unusual currents, he said.
The fallout from the tsunami came at the best time for mussel harvesting. Some marine farmers would have to spend days untangling lines and could lose about 10 per cent of their crop, he said.
He estimated the damage and loss of income at hundreds of thousands of dollars.
The extent would not be known until all the lines were fixed.
Tsunami generated by earthquakes in Indonesia in 2004 and Chilelast year had also damaged mussel farms, he said.
The solution was to use thicker anchor lines and heavy duty anchors.
Port Underwood marine farmer Paul Thomas said five mussel lines he owned were among about 16 damaged in Kaikoura Bay. Anchor ropes on about four lines snapped and drifted about 150 metres, Mr Thomas said.
"When we were over there it was supposed to be high tide, but it looked like the tide was right out"
Mr Thomas's father Ray said lines in the bay were all "tangled up in a ball" on Sunday.
Hebberd Marine Farm Services owner Maurie Hebberd, who owns about 100 lines of mussels in Croisilles Harbour, said the tide had come in and out every 15 minutes from late Saturday afternoon.
"A guy was unloading his boat at the boat ramp and by the time he got back from parking his trailer the water had left the boat behind."
The currents had broken or twisted anchor ropes on about 15 of his mussel lines, with about 15 lines damaged on other farms in the area. The "tangled mess" could take up to 10 days to fix.
"This is worse than about six years ago [after the Indonesian tsunami] that did damage to six mussel lines."
There have been no reports of damage to farms in Tory Channel or Pelorus Sound.
Sanford Mussel Farm Havelock branch manager Wayne MacDonald said lines on one of its farms had moved at the weekend, although they were not sure what caused this.
Repairing the damage should not cost too much and was a normal part of working on a marine farm, Mr MacDonald said.
NZ King Salmon general manager for aquaculture Mark Preece said there had been no reports of unusual currents at any of the company's five marine farms in the Marlborough Sounds.
Marlborough harbourmaster Alex van Wijngaarden said he had not heard of damage caused by the tsunami, although there had been a few "weird" currents close to Picton.
National Institute of Water and Atmospheric Research principal scientist in coastal hazards Dr Rob Bell said strong currents were common around New Zealand following the tsunami.
The surges could bounce off the side of bays, which created erratic currents, Dr Bell said.
- The Marlborough Express