Forest & Bird South Otago co-chairman Roy Johnstone said yellow-eyed penguin (hoiho) nests in the Catlins, and nationally, had suffered a huge population decline.
The protest was aimed at spreading awareness and featured several people dressed as penguins and a small yellow-eyed penguin plushie being carted around on a stretcher.
Long Point, near Purakaunui in the Catlins, is a significant nesting spot for the birds, but had seen a steep and steady decline since their peak in 2013 when there were over 50 nests.
That number has fallen to under 10 last year.
"We’ve had huge starvation over that time, then later in the season there was a lot of marine predation — the adults are dying and the chicks are dying."
The starvation made the penguins more susceptible to diseases such as avian malaria and and diphtheria, lowering numbers even more.
While Forest & Bird and the Yellow-Eyed Penguin Trust were protecting the birds on land, the marine environment was the problem.
"We’ve had a five-year plan to boost numbers, but it just hasn’t worked, and there has been a 37% decrease in that same time — the situation is quite desperate."
He said all their efforts were "bottom of the cliff stuff", but there was no ambulance waiting to fix the issue.
Yellow-eyed penguins fed from the sea floor, but marine trawling was damaging the ocean floor and taking away the penguins food source.
"We need marine protected areas, and we’ve been advocating one at Long Point.
"It was agreed to as part of the Southeast Marine Protection Forum, but when everyone agreed, it was vetoed.
"We have no marine protection in the Catlins."
Mr Johnstone said the process to get marine protection in the Catlins was a slow process bogged in bureaucracy and while that all happened more and more yellow-eyed penguins were starving to death.
"Trawling has trashed their feeding grounds — they used to have squid, red cod, opal fish and from tests we’ve tested their poo and we can see they are relying on blue cod.
"If there is not enough food for them to eat, then they die, it’s that simple."
