The sunken cars license plate is 'Louisiana 007 o 981' This plate is used in several shark films throughout the years. The first instance was when Hooper (Richard Dreyfuss) pulled it out a tiger shark in Lo squalo (1975). The same license was pulled in Blu profondo (1999) by Carter Blake (Thomas Jane) from another tiger shark.
Despite the story of the film being about a Bull Shark, the poster displays a Great White Shark.