The draw of Discovery’s Shark Week promo stunt this year, which pitted Olympian Michael Phelps against a great white shark, was big. David Zaslav, president and CEO of Discovery Communications, wanted this year’s Shark Week to be “our best ever.” And it might have been; viewers watched in record numbersThe surge from excitement around the event is also apparent in web traffic. Jumpshot data shows discovery.com and discoverygo.com saw 58 percent more traffic than the week preceding Shark Week. And this year’s Shark Week bump is 16 points higher than last year’s, which saw a 42 percent increase than the previous week.

Though surge of interest from the Phelps event was proportionally bigger this year, it wasn’t enough to make up for a decrease of traffic this year compared to last. Overall, our analytics show there were 7.2 percent fewer overall visitors this Shark Week compared to last year. The week before Shark Week was down even more, 16.8 percent lower this year than 2016.

And while TV ratings for almost all Shark Week programming was up this year, Jumpshot’s data doesn’t show a comparable bump for Discovery’s YouTube viewership. In fact, the Discovery channel is fairly quiet, tending to play well with Mythbusters fans. On the day that drove the most traffic to Discovery’s YouTube channel, the video Phelps Vs Shark: Making Michael Faster didn’t even catch one tenth of the views for the most popular video, Is it Possible to Curve a Bullet, and last year’s top Shark-themed video Great White Naps for First Time on Camera only garnered 40% of the views of the leading Mythbusters videos.

So what gives? Shark Week has been an annual, high-summer tradition at Discovery Channel for almost three decades. The channel has effectively harnessed attention and enthusiasm out of the dread and mystery and fascination that surround sharks, which is well established as a true “celebrity species” among marine biologists. But this year, when the great white turned out to be computer generated, viewers weren’t exactly pleased.

Older shark videos on YouTube have proven they can generate viral appealshark attack videos like this one, and this one, have garnered 17 million and 11 million views, respectively. With that it mind, maybe the online numbers for the Phelps event, and Shark Week in general, would have been significantly higher if he had raced the real thing.