Continuity mistake: In the opening credits, there are eleven skiers in the pyramid. However when they fall in the water, and then all get up and ski off again, there are only ten skiers now. (00:02:00)
Continuity mistake: At the beginning of the movie with the scene of the water skiers, the amount of boats on the water goes from hardly any, to suddenly being loads. (00:02:35 - 00:03:40)
Continuity mistake: In the beginning when the water skiers are practicing, in one shot they are skiing right next to land and trees, in the next shot they are way out in the ocean near the ports. (00:03:25)
Continuity mistake: When two divers emerge from the water, one pulls their goggles up onto their forehead and the other pulls his goggles down to round his neck. Then the divers and Mike start talking about 'no overtime', and between shots the goggles around the divers neck vanish. (00:07:30)
Continuity mistake: When Dan walks down to a podium and looks over to see the dolphin knocking at the gate, the tee-shirt he is wearing changes from being plain white with a tag badge on his left, to a white shirt with a large blue stripe across it, with a tag badge being on the right. (00:08:20)
Continuity mistake: In the breakfast scene with Mike and Sean, the angle of the Tropicana juice carton keeps changing. (00:26:10)
Continuity mistake: In the breakfast scene, as Mike walks over to the table with the pot of coffee, the amount in the pot changes from barely full to almost full to the top as he sits down. (00:26:35)
Continuity mistake: In the kitchen scene when Mike and Sean are eating breakfast, the phone cord hanging behind Mike keeps changing from being loose and free, to all twisted and tangled. (00:26:40)
Continuity mistake: When Mike answers the call from Calvin the phone cord goes over his shoulder. When it cuts it's gone. (00:27:10)
Continuity mistake: When Mike has the harpoon pointed for the sharks dorsal fin, there is white rope wound around the length of the metal harpoon. In the shot just before he shots the harpoon, there isn't.
Continuity mistake: When the shark is chasing the water-skiers, you can see its fin is about 3 feet behind them, meaning its head must be underneath, if not in front of them. However, in the shot from under the water its viewpoint is shown as being behind them.
Continuity mistake: After the big shark dies Mike and the blonde girl are calling the dolphins, in one shot it's dawn and it's dark but suddenly in the very next shot it's completely daylight.
Continuity mistake: The size of the small shark decreases a lot when it is caught.
Continuity mistake: When Mike is in the water doing the welding on the tunnel patch he is wearing a full face mask with the rebreather attached at middle, but when he and Kay are swimming away and go into the door back to the control room after being chased by Jaws, he is wearing just a regular snorkel mask with the rebreather in his mouth.
Continuity mistake: The small shark shrinks a lot when it's brought into the enclosure. If it were its original size, it would have stuck halfway out of the tank.
Answer: The lagoon was part of the theme park. Artificial with specific mammals inhabitants inside, warm and friendly.