"You can tell from gestures ... Even if she had no English whatsoever, she knew exactly what I was trying to tell her."
She ended up putting the bag in slightly deeper water for later retrieval, Raines said.
"I don't want it to be a witch hunt. I want to make people aware," he said.
As a local, he knew all about the ban and why it was in place, he said, adding that it used to be a really healthy seabed.
"I'm not a grand-stander," he said.
"I am really passionate about the marine environment.
"I'd really like to see that beach build up again, it's a really fragile marine eco-system."
He hoped the video would empower others to speak up as well if they saw something similar happening, he said.
"It's about the local government departments, locals and iwi all being involved to try and replenish this area."
The Ministry of Primary Industries has been contacted for comment.