Gee, was it that obvious? That the good looking and very nice male and female leads would survive, and the egotistical jerk would be shark meat? I called this one by the end of the 2nd commercial break. 
Unlike Jaws (where the shark looked somewhat real), there was not just one shark but many. Swimming in formation like Luftwaffe. That was perhaps one of the funniest visuals of all. I think the effect was done by attaching a bunch of dorsal fins to a board and dragging underwater. It was to laugh.
JT met the sharp teeth of poetic justice when he was trying to make time with yet another babe. When the attack came, he pushed her out of the way (and into harms way) so he could get to safety. If we weren’t convinced of his jerkitude by this point, we were now. Luckily for all of us, he slipped and fell victim to nice chunk of papier mache with teeth. Yay!
Anyway, Babe Chick, her Nerdy Brother, and Mama’s Boy lured the nasties away by dragging a bucketfull of chum out to sea. The sharks followed (in formation, of course). The sharks ate the boat’s engines. (“What do we do now?” “I don’t know! I never read that chapter!”) Nerdy Brother then put his high-tech shark repellant pods in the water. Although they have never worked before, he was willing to risk his and his sister’s lives on them now.
Except when he put them in the water, one malfunctioned. It was wired wrong! So did he pull it up to fix it? Of course not. He sent his sister down. And she only had thirty seconds of air in her lungs before she would drown! Could she fix it by then?
Big stupid predictable climax, then everyone’s OK. Evil Australian dude was renting the boats to seed the water with chum, to attract sharks, scare off the tourists, and get the tourists back to his own resort. He got arrested. Nerdy Brother got his Ph.D. in Sharkrepellingology. Angry Dad reconciled with Babe Chick. Babe Chick and Mama’s Boy decided to meet in Cancun next year.
And they all lived happily ever after. Or served time. Or digested easily.
The strangest bit was the commercials. Almost all of them were for cruise lines to Florida. 