Dunedin man Ate Heinman, who was a commercial fisherman for 47 years, said he was disappointed in the decision because of the impact it would have on fishing.
"People are going to have to shift their effort away from those reserves and sit on top of someone else.''
Fishing areas would become crowded, and potentially some businesses could fail, he said.
Although the ocean was a big place, different species were caught in certain places, he said.
"You can't just chuck a line over your boat anywhere and catch a grouper.''
Fergus Sutherland, who previously owned Catlins Wildlife Trackers, said for tourism the move was a "very positive outcome''.
"It will protect wildlife and make fisheries more sustainable.''
"We all know that the yellow-eyed penguins are in dire straights at the moment and that's of concern to tourism operators.''
It was a shame the forum group could not get better protection in the Otago Peninsula, he said.
University of Otago marine science senior lecturer Chris Hepburn said the network was a "good first step''.
The scientific community he represented on the forum wanted a lot more marine protection, he said.
Fishing was definitely something which needed to be controlled to protect marine biodiversity.
However, there were many other problems which needed to be faced, including the impact of sediment going from land to sea.
"All of these things are connected, but we had one tool - to control fishing.''
