Factual error: The shark that attacks the Brodys in the Bahamas is presumably the same one that kills poor Sean Brody on Amity Island (that poor kid can't catch a break). Ellen departs for the Bahamas after Sean's funeral and the shark follows shortly thereafter. So, the shark swims from Amity, an island off the North Atlantic Coast, down to the Bahamas in order to stalk Ellen, Mike, etc. in a matter of days. Hmmm. As Matt Hooper said in the first film, "fast fish".