"I wasn't expecting to get 10 messages from people so quickly," he said.
Within hours Pettigrew was flooded with positive feedback, about which he was pleasantly surprised. Among the messages were requests from a large international school and a school in Britain eager to hear Pettigrew talk via Skype.
"I really didn't think I'd get the response I did. I literally thought it would get bumped further down the page and not really be seen by so many people."
Talking to young people and sparking an awareness and interest in the ocean and sea life was the biggest reward, he said.
"It's cool for the kids. They love it. They see things from my world that perhaps they would never see. So I really want to share that," he said.
"It's the first time I've ever gone out and pushed it. I didn't want to annoy anyone, especially busy teachers."
Pettigrew is now organising visits with the interested schools. He is also eager to promote the importance caring for the ocean and keeping plastics out of waterways.
"It's important that we all give back somehow or pay it forward in some way and I'm in a unique situation where my experiences would be wasted if I did nothing with it.
"Kids are the key to our environmental future and I simply aid in growing a kid's imagination in the hope that they are our future kaitiaki, or guardians."