Protected white-fronted terns hang dead from fishing nets strung up on a boat in Oamaru Harbour. Photo supplied.

Just metres away from the Oamaru Creek Penguin Reserve at Holmes Wharf, members of another protected bird species have been dying "horrible" deaths after being caught in fishing nets.

Dead white-fronted terns hanging from unattended open-weave nets draped over moored fishing boats are a daily sight at Oamaru Harbour and one Oamaru couple, fed up with cutting dead birds down, are calling for the nets to be banned.

Carl and Fleur Newton have been keeping a record of how many birds have died, and have managed to rescue some of them, but they said more needed to be done to save the birds from their plight.

Mr Newton said that over the past six weeks he had seen as many as 30 of the protected terns caught up in the nets, and had notified the Department of Conservation (Doc) about the situation.

Doc had been very supportive but fishing boat owners were taking little notice, he said.

"They [Doc] sent a letter out, which went out over two weeks ago and nothing has been done, no nets have come down.

"I think the trouble is, too, that people don't know about it.

"Once I noticed it and started to look around, you see what's going on."

Mrs Newton said her husband, a keen rower, had managed to rescue eight birds from the nets, but not all of those that had been cut free had survived.

"Doc ended up with four and we released four back into the wild.

"The four Doc ended up with had to be euthanised, because of their injuries. It is a horrible way to die."

Doc Coastal Otago biodiversity assets programme manager David Agnew said most sea birds, including terns and shags, were "absolutely protected" and there were "thousands" of shags alone in Oamaru Harbour.

"Under the Wildlife Act, protected species should not be trapped or killed.

"We appreciate the boat owners' perspective, but we know there are a lot of effective methods out there that they could apply."

Mr Agnew said the department acknowledged that there was no intention from boat owners to trap the birds on purpose, and Doc had made boat owners aware of the issue.

It was now up to them to find a "good solution", he said.

andrew.ashton@odt.co.nz