The episode spoofs Jaws in several ways. In one scene the music teases the famous shark theme when Doc tells the kids something dangerous is in the pool. The next scene, he's warned that businesses can be hurt if there's "another water scare" in the town, that relies on tourists, like Amity Island in Jaws.
A lady walks up to Martin on the street and tells him her child has a tummy ache. She says her name is Mrs. Braithwaite and her daughters name is Emily. Martin Clunes is married to Phillipa Braithwaite in real life and their daughters name is Emily.