A review of monitoring results for fish farms in the Marlborough Sounds by Scottish specialist Kenny Black would be a starting point for discussion on new standards for the industry. Reporter Penny Wardle looks at his report, leaked to protest group Sustain Our Sounds after being commissioned by the council.
Dirty fish farms often perform badly and attract bad press, which reduces demand for the fish, says aquaculture specialist Kenny Black.
This means corporate fish farmers are the main beneficiaries of rules protecting the marine environment they operate in, he says.
The Marlborough District Council employed Professor Black, from the Scottish Association of Marine Science, to review its analysis of monitoring results for six New Zealand King Salmon farms in the Marlborough Sounds.
The monitoring was done by Cawthron Institute, which used robust methods to check the NZ King Salmon farms, he said.
Effects on the Sounds seabed seemed similar to Scotland, where salmon had been farmed since the mid-1970s.
The main reason for limiting pollution under fish cages was to ensure there were high numbers of burrowing creatures such as worms, Professor Black said in answer to questions from the Marlborough Express.
Worms aerate the sediment and break down the organic waste. If worms die, toxic sulphide could concentrate near the seabed, endangering farmed fish and wild animals that cannot swim away.
NZ King Salmon said it would respond to Professor Black's review at a council environment committee, but in the past chief executive Grant Rosewarne has said worm numbers are carefully managed at farms to break down waste.
However, in draft 2012 monitoring reports sent to Professor Black, the council describes little or no oxygen or signs of life below NZ King Salmon fish cages. Sulphide levels are high in places beneath the farms.
Professor Black questions the different standards applying to the NZ King Salmon consents. He suggests they should all be the same.
"Ideally, all . . . sites can be brought into a common consenting framework with common standard, " he said.
For example, the consent for the Waihinau farm established in Pelorus Sound in 2000 had fewer conditions than the consent issued in 2009 for Te Pangu in Tory Channel.
Cawthron monitored all farms to the highest standards, but to comply they needed to meet only the original consents.
Professor Black cautions that waste at fish farms around the world was not being flushed away as efficiently as the operators expected.
He confirmed that NZ King Salmon had breached conditions at one of its farms, at Clay Point, last year by feeding out more pellets than allowed. This month a council commissioner granted the company a backdated consent which made the breach legal.
The situation in Scotland was different, Professor Black said
"Standards are standards and if someone was non-compliant, then a retrospective consent wouldn't help."
Waihinau, where an estimated 125,000 fish died last year, might not have been deemed non-compliant if a more modern consent was in place, he said.
NZ King Salmon had reported significant declines in production levels as two farms produced more waste than the environment could absorb and two others came close, he said.
The company had since offered to standardise consent conditions for its farms. Professor Black questioned the way Cawthron altered the importance given to environmental measures from site to site.
Added up, these decided whether a site was compliant.
"I would strongly urge that a piecemeal approach to weighting will only result in pressure to manipulate the results to obtain the desired result . . . and will make the system unworkable, " he said.
NZ King Salmon should be be allowed to rest farms for the seabed to recover between cycles only if it was never allowed to break standards, he says in his report to the council.
The company regularly rotates the Waihinau farm with its Forsyth site in the outer Sounds.
Instead of fallowing, management could be adjusted by reduced feeding, moving fish on or off-site and earlier harvesting, he told the Express. If sites were rested, monitoring should be done more frequently to improve public confidence.
The company did not pay any lease for its space in the Marlborough Sounds so "the small increased costs of such monitoring do not seem disproportionate", Professor Black said.
An Environmental Protection Authority board of inquiry last year gave NZ King Salmon consent to build four new farms at high flow sites. Action groups Sustain Our Sounds and the Environmental Defence Society last month went to the Supreme Court in Wellington to have the decision overturned after an earlier appeal to the High Court was rejected.\
LARGE-SCALE IN THE RADAR
The days of large-scale fish farming on inland waterways such as the Marlborough Sounds could be numbered, says Scottish fish-farming specialist Professor Kenny Black.
Marlborough fish farmers should consider moving out of the Sounds even a little so farms are exposed to ocean swells, he says.
In a report for the Marlborough District Council, he says the global trend is towards bigger farms at more exposed sites to drive down both costs and any damage to the environment.
In answers to the Express, he says the industry in Scotland is outgrowing the fiordic sea lochs and expanding into more open waters with some shelter.
Hawaii is the most advanced in open-sea farming using submersible cages. One of the latest developments is research into growing tropical kampachi fish in pens moored 10km off the coast and well below the sea surface.
Opponents of fish farming in the Marlborough Sounds have suggested companies such as NZ King Salmon should set up land-based pens with sea water pumped through them.
This was not yet happening in Scotland, Professor Black said.
While he is in Marlborough, Professor Black will be part of discussions between the council, NZ King Salmon, the Ministry for Primary Industries and various sector organisations to establish a set of guidelines for salmon farming in the Marlborough Sounds.
Professor Black will give two public presentations explaining how Scotland faced the environmental issues in aquaculture.
"The Evolution of the Scottish Salmon Industry"
Tuesday, December 10, 7pm, Marlborough Convention Centre, Blenheim
Wednesday, December 11, 3pm, Portage Hotel, Kenepuru Sound
- The Marlborough Express