Trial and error over time

New Zealand King Salmon would "learn by doing" if it is allowed to build nine new salmon farms in the Marlborough Sounds, planner Sarah Dawson said in Blenheim yesterday.

Ms Dawson ended three days of cross-examination by answering questions from members of the Environmental Protection Authority board of inquiry which will decide whether the nine farms can be built.

"In normal practice if you could not set thresholds, would this be a show-stopper," commissioner Mark Farnsworth asked.

Ms Dawson said she had worked on other applications with no hard and fast thresholds. "There are situations where it is necessary to write the outcomes in words rather than numbers," she said, adding that the words in King Salmon's consent conditions would be developed to numbers refined over time.

Experts agreed it would take 10 or more years to gather information describing the environment from the surface to the seabed.

Serious problems could develop in the water column but they could be quickly reversed and the risk was low, Ms Dawson said.

Mr Farnsworth asked whether from an aerial perspective the Marlborough District Council planning had successfully protected the Sounds.

At a Sounds level, yes, Ms Dawson said, but the Waitata Reach of Pelorus Sound was compromised by the number of marine farms.

Asked how a planner could measure their success, Ms Dawson said a good outcome at this hearing would be approval of the plan change and resource consents applied for by King Salmon. Ongoing success would be accomplished by adaptive management, conditions, robust peer review and the setting and achieving of thresholds.

Ms Dawson agreed with board commissioner Helen Beaumont that wording of the proposed plan change implied support for continued expansion of salmon farming. The words could be changed to enable the farming of salmon by identifying appropriate sites, she said.

Asked by Ms Beaumont whether the application set up the potential for King Salmon to monopolise fish-farming space in the Sounds, Ms Dawson said the Sounds was not teetering on the point where no more effects could be assimilated.

However, she agreed future applications could threaten the viability of King Salmon by overloading water with fish waste and threatening biosecurity by reducing the distance between clusters of farms.

King Salmon was submitting on two such applications heading to appeal after being considered by the Marlborough council, Ms Dawson said.

The application did not allow for the use of antibiotics to be included in feed, Ms Dawson said.

If there was a disease problem, the company would use other measures such as vaccination and good husbandry.

The Marlborough Express