The program, "Megalodon: The Monster Shark Lives," opened Discovery's annual "Shark Week" during the weekend. With an estimated 4.8 million viewers, it had the largest audience of any show in the 26 years that Discovery has made "Shark Week" a part of its summer programming, the Nielsen company said.
Yet it drew a heated response online from viewers who said airing a "mockumentary" compromises the network's reputation.
"It's the ultimate 'Shark Week' fantasy," said Michael Sorensen, Discovery's senior director of programming. "The stories have been out there for years, and with 95 percent of the ocean unexplored, who really knows?"
Discovery's "Shark Week" Web page and Facebook and Twitter sites filled after the show with complaints from fans who objected to the program, saying they were surprised a science-based network seriously discussed the existence of a fearsome creature when there is no evidence it exists today. The "Megalodon" special was reminiscent of two shows on sister network Animal Planet about mermaids, which also got big audiences.
In a blog post, actor Wil Wheaton said he is a regular viewer of "Shark Week" but he was disgusted by the show. He said Discovery owes an apology to viewers who have grown to trust the network for its presentation of science.
"Discovery Channel betrayed that trust during its biggest viewing week of the year," Wheaton wrote. "Discovery Channel isn't run by stupid people, and this was not some kind of a mistake. Someone made a deliberate choice to present a work of fiction that is more suited for the SyFy channel as a truthful and factual documentary. That is disgusting."
Discover magazine's Christie Wilcox wrote that the show's "evidence was faked, the stories fabricated, and the scientists portrayed on it were actors. The idea that Megalodon could still be roaming the ocean is a complete and total myth."
Wilcox wrote that "You used to expose the beautiful, magical, wonderful sides of the world around us. Now, you just make (stuff) up for profit. It's depressing. It's disgusting. It's wrong."
At the end of the special, Discovery aired three disclaimers. Discovery said that none of the institutions or agencies that appear in the film is affiliated with it in any way. The network also said that "though certain events and characters in this film have been dramatized, sightings of 'submarine' continue to this day." Discovery would not say what events that referred to.
"Megalodon was a real shark," Discovery told viewers. "Legends of giant sharks persist all over the world. There is still debate about what they may be."
For Discovery, the question is whether the short-term achievement of high ratings is worth the risk of alienating long-time fans.
People watch Discovery to explore the "what ifs" of the world, said network spokeswoman Laurie Goldberg. The special "used a novel storytelling device to engage that imagination and curiosity in a way that was disclosed to audiences throughout the program," she said.
"We have found that people are open to exploring different ideas and concepts in addition to the more traditional fare that we air," Goldberg said. "That would explain the ratings. As in any entertainment, you aren't going to always please everyone, but we stand behind all of our content and are proud of it."
Sorensen talked before "Shark Week" about embracing the annual programming stunt as a pop culture event. For the first time, Discovery is showing a nightly "Shark Week" talk show hosted by a comedian.