The victims were freed unharmed after the alleged payment of "protection" fee to pirates operating in the area.
The military said the victims were sailing southwards when the sea marauders on board a twin-engine speedboat named Manila Boy at about 5 p.m. Saturday off Tukuran, San Carlos town, intercepted them.
Maj. Eugene Batara, Western Mindanao Command information chief, identified the leaders of the suspects as a certain Kamil Lao.
He said the pirates abducted the fishing boat crew and held them somewhere off Illana Bay in Zamboanga Del Sur for hours.
Investigation disclosed that the suspects took the fishermen hostage after the fishing boat owner — Ronnie Iyas — allegedly failed to pay "protection" fee to the group.
The victims were only released Sunday after their fishing boat operator reportedly paid P160,000. None of the hostages was harmed during their captivity.
Government forces have intensified patrol along the coastal village in Tukuran, which is said to be a pirates-infested area.