"Sharktopus 4" was announced in the film's closing credits, but it has not been made to this day.
Fun fact: Casper Van Diem divorced his wife Catherine Oxenberg in 2015, the year that this film was released, and married Jennifer Wenger, the woman who played Nurse Betty in it.
The working title of this film was "Sharktopus vs. Mermantula."
The whalewolf is actually based on a creature from Inuit mythology called the akhlut, an orca-like composite animal that takes the form of a wolf when on land, and has sometimes been depicted as a wolf-orca hybrid.
Casper Van Dien plays Captain Brady, which may be an homage to Chief Brody from the "Jaws" franchise. Both men have had to deal with sharks.