"There was so much hype about the Million Dollar Fish," recalled Jarrod Godson, who runs the Reel Screamin' Barramundi Fishing charter company in Darwin.

"We went from five days [of bookings] to 15 days a month, which was unreal for us."

In the first two seasons, more than 43,000 people around Australia registered for the chance to catch the country's most lucrative fish.

But since then, registrations have fallen significantly, according to a consultant's report commissioned by the NT Government at a cost of $255,000.

The report, obtained by the ABC through a Freedom of Information request, showed the number of entrants went down to 32,100 in season three and 23,648 in season four.