Here's why:
* He's framed by the real criminal, a notorious poacher named "Big" Ed. Ed wants to silence Father, who knows the truth about his illegal activities, and he manipulates the authorities to make Father look guilty.
* The evidence against Father is fabricated. Ed plants evidence, like an illegal alligator egg, in Father's boat and makes it look like he's poaching.
* Father's stubborn refusal to cooperate with authorities makes him appear suspicious. He doesn't want to expose the truth about the real poachers because he's afraid of putting his family in danger.
* The authorities are corrupt. They are easily swayed by Ed's influence and choose to believe the fabricated evidence.
Father's imprisonment is a tragic injustice, and he is wrongly convicted. He spends a significant amount of time in jail before he is eventually exonerated and released.