From the fishermen themselves to the tuna spotters, radio workers and families and friends who were left at home while the fish were being caught, the documentary has covered all areas.
Mr Kerr said he interviewed more than 30 people over the two years it took to make the documentary to get a diverse range of history.
"We have tried to capture different facets of the industry from the early days, from the big days when they were poling a lot of tuna, the women's stories and their support being home with the kids.
"Then there was the social scene and then the downturn of the fishery and we touched on the resurgence of tuna farming and value adding."
Mr Kerr said there were many stories told to him and there are many he would describe as his favourite.
"Of course there was the big story of the gun fight in the Great Australian Bight which we got from the people that were there and the stories from the early days were really interesting too."
Mr Kerr has written many books as well, but he says oral history is a great way of preserving many memories.
"Recording these guys when they were still alive, expressing what they did in their own way and through film you can actually hear and see the people involved, which adds another dimension to it.
"You can't do these things soon enough becasue I go to so many places where people say 'oh you should have been here ten years ago to talk to my dad' and so I am trying to do more."
And after 11 documentaries on fishing, Mr Kerr has decided he will start researching for his 12th one.
"I am thinking it will be on the deep sea trawl fishery, in particular the orange roughy boom, which a lot of Port Lincoln fishermen were involved in."
What happens on a tuna boat....stays on a tuna boat
Back when the industry was attracting a lot of new fishermen to Port Lincoln, two sisters found themselves hanging around at the jetty a lot more.
Helen Griffin and Pauline Heinonen grew up in Port Lincoln and their father was also involved in various fishing industries as well.
They had fishing in their blood and when the tuna boys arrived they had a great time hanging out with them.
But as they explained in the documentary, some stories are better left to the imagination.
"I think it was pretty self explanatory in this wonderful documentary that has been produced, but those were the days, we had some wild parties on those tuna boats I can tell you," laughed Ms Heinonen.
And while older sister Helen was in a relationship with one of the fishermen, Pauline, as the younger sister, got to tag along with the fun as well.
"I was only about 15 at the time, so I was really more an observer in a lot of it, but it was good fun.
"These guys were terrific and they were diffrent from the local guys and they were interested in different things'.
"The best thing was they taught me how to water ski on Boston Bay and the tender boat they used to spread the nets, they used to burn around and I got to learn to ski...it was fantastic."
But it wasn't all fun and games, the men worked hard and sadly, Mrs Griffen remembers when a boat was lost at sea.
"There was a few tragedies, one boat went down with all its crew, my girlfriend was actually going with one of the lads on that boat."
Ms Heinonen said to be a part of the Those Were The Days documentary was pretty special.
"I love what Gary has done becasue he has documented the early fishing days and the early maritime history of our state.
"For us it is a part of our history and the history of this town and we just love it."
Too many stories
Port Lincoln local and tuna fisherman Ross Haldane joined the project early on as a researcher.
"This history is part of our family, and so I knew the basics of it, but it was fascinating as we started to dig deeper how many early gems there were in the history that had been forgotten," said Mr Haldane.
"It's been an amazing journey- the hardest part was making cuts. There were lots of stories that didn't make the final documentary, but were just fantastic."
Mr Haldane is adamant that they will make the approximately 80 hours of unused oral history available to the public in the future.
