How many movies have Howard Schwartz and Joseph Barbera collaborated on?

They have worked on 3 movies together! Their first movie together was Scooby-Doo on Zombie Island (1998) while their highest rated movie together was Scooby-Doo! and the Sea Monsters (2012). They have not worked together since Scooby-Doo! and the Sea Monsters (2012). They are most known for their family films together.