Recreational fishers, including spearfishers, are not allowed to bag wobbegong sharks in NSW.
Officials worked with police to carry out a search warrant at the fisher's home.
They found 2.78kg of wobbegong shark flesh inside the fridge at the property, as well as diving equipment, including a speargun.
The DPI claimed the man admitted to unlawfully taking the shark.
He will now face sanctions over the event.