Xtinction: Predator X (2010)

When her father seemingly goes missing, divorcee Laura LeCrois is forced to return home after a 20-year hiatus. However, home is not the way Laura remembers it. Her father is in major debt with the bank, her ex-boyfriend is the town sheriff, and her ex-husband has quit his job as a world-renowned professor who is now suspiciously buying up swampland in the area. In an effort to save the swamp and to pass the time, Laura decides to work the dying family business giving boat tours of the Louisiana swamp. But on her first sunset tour, deep in the swamp, Laura and her passengers witness two Bayou swamp rats toss a squirming body into a gator pit, only the gators aren't the ones that feast on the flesh. Instead it's the most terrifying creature Laura has ever seen...(IMDB,com)

Source: TMDb