The businesswoman, identified by her last name of Tseng, was ordered to spend six months behind bars. The verdict was handed down Monday by the court in the western port city of Puntarenas.
It was the first criminal sentence in the country against the practice of shark finning, which involves slicing off a shark's fins before dropping the live fish back in the sea. Unable to swim effectively, the wounded creature faces a grim future: suffocating, starving or being eaten.
Tseng's was "a historic sentence," said Gladys Martinez, lawyer for the Interamerican Association for Environmental Defense (AIDA).
Her case began in October 2011, when her fishing boat, the Wan Jia Men 88, was found with 151 sharks aboard. Their fins had been chopped off.
She was initially acquitted in 2014, but the matter went to appeal, and the Puntarenas court this week found her responsible for damage to Costa Rica's natural resources.
The Central American country, known for its biodiversity, has ratified several treaties for the protection and sustainable use of marine resources.