The scene showing the foot of a woman with a shark fin tattoo was not in the script. While still filming in Lake Tahoe, an extra involved pointed out her real-life tattoo to the cinematographers. They grabbed a shot of it, which ended up in the final cut of the film.
Originally called and to be produced under the title "The Lake" with the story set at Lake Tahoe in Nevada. The title was changed among other things when the filming location was moved to Biloxi, Mississipppi.
Their ability to tolerate freshwater is rooted in salt retention. Sharks must retain salt inside their bodies. Without it, their cells will rupture and cause bloating and death. Given this requirement, most sharks cannot enter fresh water, because their internal salt levels would become diluted.
Feature film debut for commercial director Jerry Dugan.
Hannah Jacole Powell-Yost's debut.