For 31 years, the Discovery Channel has entertained viewers with its yearly pop culture phenomenon Shark Week, wowing viewers with programming like this year's opening documentary, "Expedition Unknown: Megalodon" or other shows like "Great White Kill Zone: Guadalupe" and "Sharks Gone Wild."

Shark Week, which kicks off Sunday at 8 p.m. ET, drew nearly 35 million total viewers last year, according to Nielsen, and those numbers help provide conservation efforts with unmatched potential publicity and fundraising. But some shark biologists think that not all publicity is good publicity and are condemning the choices the cable network is making to reach wider audiences — worried that there's too much focus on sharks' grisly attacks on humans and not enough on the science and conservation.

This year, Discovery is debuting its first fully scripted Shark Week drama — "Capsized: Blood in the Water," based on a real 1982 incident in which a yacht crew was stalked by tiger sharks after their boat sank during a storm. Amid the blood and screaming, the film that premieres on Wednesday at 9 p.m. is not expected to linger too much on science.

"It’s really disappointing that you have so much potential with a really interesting subject and that potential is lost because they focus on sensational aspects," said Dr. Stephen Kaijura, a shark expert at Florida Atlantic University.

"Here you have a really diverse group of animals — they are a fascinating group because of their diversity and evolutional history. But so much of that is ignored with shows called 'Blood in the Water' or 'Danger Beach.'

"You’re missing out on an incredible opportunity here."

Josh Duhamel in a scene from "Capsized: Blood in the Water." Discovery Channel

But Discovery has inarguably also provided a lot of positive opportunity for the field and has even given back.

“I think at the end of the day given the popularity of Shark Week and the reach that Discovery has globally, we can bring more people into the tent," Howard Swartz, the Discovery executive who oversees Shark Week, told NBC News. "And however we can do that, we will try to reach as broad an audience as possible."

By reaching that broad audience, the network has helped raise millions of dollars for conservation, including $1 million alone for the environmental charity, Oceana, over the past 10 years. Discovery has also supported lobbying for anti-fin legislation, and regularly gives press access to scientists during the media surge ahead of Shark Week.

Working with the group, Ocean Conservancy, for the second straight year, Discovery hosted beach clean-ups in Los Angeles, New York City and Knoxville on Saturday.

Though he's not affiliated with Discovery anymore, Andy Dehart said he found Shark Week to be a "powerful platform" during his five years as a shark adviser to the network from 2008 to 2013.

"It's allowed me to travel the world to talk about science and conservation," said Dehart, now VP of animal husbandry and marine conservation at the Phillip and Patricia Frost Museum of Science in Miami. "Having worked with them, I've seen Shark Week has that type of draw where they can get Fox News (for example) to talk about another network."

"For 31 years, Shark Week has been all about celebrating sharks," said Swarz. "That’s our guiding principle."

That doesn't mean the choices aren't a little misguided, say critics.

One programming choice The Discovery Channel would probably like to take back is the ill-received 2013 fake documentary surrounding modern-day attacks by prehistoric megalodons. Considering the prehistoric sharks are actually long extinct, the special that fooled many viewers is still held up by detractors as an example of network irresponsibility.

"It was very detrimental. To this day I still have people who are convinced there are really megalodons out there," said Kajiura. "They misled the public, and that was a real breach of trust as far as the scientists are concerned."

More recently there have been a number of celebrity driven shows — like the "Shark Trip: Eat. Prey. Chum" special airing Sunday at 9 p.m. that centers on comic actor Rob Riggle getting his famous friends to swim with sharks — that can come across as gimmicks.

“The voice of celebrities could have very positive effects in terms of conservation messaging but I’m not sure that messaging always breaks through," said Dean Grubbs, assistant research director of Florida State University's Coastal and Marine Laboratory.

"I do wish they would spend more time producing shows that highlight actual scientific research and the hard work a huge number of scientists put in to studying these animals and supporting their conservation."

Spanish fishing vessel captures a shark near the Portuguese Azores, Portugal, on June 26, 2019. Greenpeace / Reuters file

But Discovery Channel is a network that depends on advertising and cable fees and that has to factor into some of the decision making, said Robert Thompson, director of the Bleier Center for Television and Popular Culture at Syracuse University.

"I can perfectly understand why scientists who want the world to be informed about the wide variety and complexity of sharks would not like Shark Week," said Thompson. "But for many people, most of what they know about the animals come from 'Jaws' and 'Shark Week.'

"They expect to be entertained."

The general strategy, though, is to use the more sensational programming to reel in viewers to stay and watch the more science-based fare — dessert to make the vegetables more palatable.

"If I was a bear scientist, I would hope there would be a bear week, so that the animals I studied would be front and center," said Dehart.

"The bottom line is Shark Week has kept sharks in the public conversation for 30 years."