The Supreme Court has given the go-ahead for three new fish farms in the Marlborough Sounds but rejected plans for a fourth site due to the area's outstanding natural character.
King Salmon initially wanted to put nine salmon farms in a protected part of the Sounds, but a board of inquiry rejected five of the sites and has subsequently faced challenges from two environmental groups over the other four.
In a written judgment on Thursday afternoon, the Supreme Court upheld an appeal by the Environmental Defence Society regarding Port Gore, but threw out a bid by Sustain Our Sounds to stop farming at the Ngamahau, Waitata and Richmond sites.
Environmental Defence Society spokesperson Raewyn Peart said the ruling to preserve Port Gore is important.
"This decision finally has said that we have an environmental bottom line in our Resource Management Act. It is an environmental piece of legislation that is extremely significant, given a lot of the discussion about the RMA and how it's applied."
However, Save Our Sounds believed the balance has tipped too far toward big business.