New Zealand King Salmon's 'inadequate' biosecurity plan criticised following salmon death investigation
Salmon covered in open wounds, unexplained fish deaths, and the discovery of bacteria never previously identified in New Zealand.
A new report has revealed the details of a biosecurity scare in the Marlborough Sounds that put the biggest salmon farmer in the country on notice.
And despite concerns over the presence of the two newly discovered bacteria, the company, New Zealand King Salmon, continued to take risks, the report says.
Berley made from salmon at risk of infection was still sent to the North Island despite the Ministry for Primary Industries saying the bait product could spread the bacteria.
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But King Salmon chief executive Grant Rosewarne defended the move by saying there were no salmon farms in the north, so the company thought there was no risk involved.
When they were notified by King Salmon, the ministry issued a notice in July 2016 demanding the company stop, a notice that was later revoked to allow the distribution of berley so long as it was treated first.
Ministry scientists discovered the two newly identified bacteria after the ministry stepped in to investigate higher than usual rates of salmon mortality in King Salmon farms in the Marlborough Sounds.
During the worst incident, in March 2015 at Waihinau Bay, more than 320 fish per 10,000 were dying a day, resulting in an overall loss of almost 70 per cent of fish at the site.
But scientists were not convinced the bacteria was solely to blame, pointing to other contributing factors such as water temperature, stocking density and nutritional stress.
The report, released in May, said wider testing following the investigation in the Marlborough Sounds found the bacteria was present in salmon farming areas outside the region.
"As such, MPI believes that the recent mortality event has a range of causes, with the bacteria possibly being involved in the fish deaths in combination with other factors."
After the bacteria was discovered the ministry implemented a range of controls under the Biosecurity Act, one of which required NZ King Salmon to apply 'status red' measures in their biosecurity plan.
But a technical advisory group assembled to provide advice to the ministry was scathing of the plan, labelling it "inadequate", "vague", and "the lack of detail ... makes the plan difficult to implement".
The group also said the production cycle of King Salmon farms was "not consistent with international best practice for the prevention of disease".
Rosewarne said there was not enough space available to aquaculture to follow international best practice of separating out year-classes, and regular fallowing of farms.
The company had already addressed most of the concerns the group had with its biosecurity plan, and the presence of the bacteria was not a major concern compared to farm location, he said.
"They've identified both major and minor concerns, the ones that seem to be getting the most attention are relatively minor ones that we've fixed," Rosewarne said.
"But the glaring, major ones, which are related to space and the quality of water, only Government can fix."
The company had since moved from its low-flow Waihinau Bay site to one about 1.5 kilometres away in a high-flow site at Waitata. Mortality rates had since dropped off dramatically, he said.
Kenepuru and Central Sounds Residents Association vice president Andrew Caddie said the "much-delayed" report made for "disturbing reading".
Caddie said since 2012 the association had "expressed its real concerns over the reasons behind these ongoing significant mortalities" at the King Salmon farms.
The association was disappointed the report was not released in time for the public hearings on the ministry's proposal to relocate up to six King Salmon farms to higher-flow sites in the Marlborough Sounds, Caddie said.
However, he said the association was working through the report with biosecurity staff and would "keep the community informed of the dangers a diseased salmon population represents to our indigenous fish species and the wellbeing of the Sounds generally".
- The Marlborough Express