Nearly half of the commercial oyster beds in Foveaux Strait have been hit by the oyster-killing parasite bonamia.
Last week, it was thought about 30 per cent of the commercial oyster beds had been affected.
But Ministry of Fisheries analyst Allen Frazer said results of another survey showed the figure was more
like 50 per cent.
This was about what the ministry expected, he said. "We knew there was significant mortality."
Bonamia was killing more oysters than fishing was, as the quota since the 90s had been kept quite conservative, he said.
Mr Frazer said fishing might be used as a tool to control bonamia in the future.
Fishermen would then be able to fish the oyster beds likely to be affected by bonamia before it hit.
This would enable them to get the oysters before the parasite spread.
The fishery would not be exhausted because the total allowable commercial catch was quite conservative compared with the number of oysters in the commercial beds, he said.
"Fifteen million oysters is a very low catch."
The fishery was not at the point of having to close, but the ministry would monitor things as the season progressed.
The fishery was recovering quite well, Mr Frazer said.
Oyster fisherman William Calder said he was catching about the same number of oysters a day as last season.
But it was taking longer to get the oysters because weeds covered some beds, making the dredges slip instead of picking up the shellfish.
- NZPA
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