Here's a hard pill to swallow: When it comes to athletic sponsorships of women, brands often seem to value female athletes more for their looks than their actual athletic merit.

The gap exists across most women's sports, if not all of them -- No. 1 women's tennis player Serena Williams, for instance, still earns less from sponsors than No. 12 Maria Sharapova. But nowhere is this "aesthetic gap" more pronounced than in surfing, a sport with sexist undertones everywhere you look.

Keala Kennelly is one of the most groundbreaking female surfers in the world, and made history in April when she beat out five male nominees and became the first woman to win the World Surf League's Barrel of the Year award.

But after 22 years in the industry, Kennelly is tired of seeing talented female surfers being held back because they don't have "model looks," telling The Huffington Post that surf companies like to "portray women like sex symbols, which is inappropriate because we're athletes."

"It’s telling [young female surfers] that it’s important to be pretty, but it’s not important to be good," she added.

The ocean is calling #MyBikini @alanarblanchard in the Mirage Colorblock Bikini Photo: @davidmandelbergstudio A photo posted by Rip Curl (@ripcurl_usa) on Mar 28, 2016 at 1:08pm PDT

"Male athletes just have to surf well," Kennelly told HuffPost. "Female athletes have to surf well, be really pretty, be really feminine and be between a certain age. We have a lot more requirements."

The issue has been receiving growing attention since February, when Silvana Lima, one of the best professional surfers in Brazil, said that companies refused to sponsor her because she isn’t pretty enough.

In the world of surfing, a lack of sponsorships not only keeps you from maximizing your earning potential -- it can also hold you back from even competing. While there is big prize money at stake once you've earned a spot in the WSL's Championship Tour, most surfers have to secure financial backing from sponsors just to travel to the qualifying events, which are held in far-flung places like Netanya, Israel, and Tahara, Japan. If a surfer can't get that initial funding together, she can miss out on the opportunity to earn a spot on the Championship Tour and compete for the prize money.

Haha thanks @hurley_lahaina for having me today 😋 A photo posted by Carissa Moore (@rissmoore10) on Feb 20, 2016 at 7:14pm PST

As the rift between "model" surfers and "high-ranked" surfers becomes more apparent, some athletes have started to take a stand. After winning a world title in 2014, Carissa Moore decided to tackle the issue head-on, penning an open letter to the surf industry that argued that all types of female surfers deserve be represented, not just "sexy" ones.

"There is a fine line when it comes to sexualizing our sport," Moore wrote. "If it is overdone, we lose respect."

Moore acknowledged that while Blanchard's "small bikinis" have helped surfing reach a wider audience, Blanchard should also be recognized as an athlete who takes the sport seriously. The industry, Moore explained, should realize that all women on the tour have unique "X-factors," which can be relatable and inspiring to all types of girls.

“I’m going to take the more athletic approach,” Moore said, adding that Blanchard's approach isn't bad, but it just isn't for her. "I think it's great that we all appeal to a different audience. That's great for our sport."

Moore's strategy seems to be working. She's currently ranked No. 3 on the world tour and is sponsored by Red Bull, Hurley, Nike, Target, Schick women's razors, 360Fly cameras and Lost Surfboards.

Neil Ridgway, head of marketing at Rip Curl Global, has insisted that all surfers, male and female, have to rank high in competition and be influential with their fan base in order to obtain sponsorships. After all, a surf brand's ultimate goal is to sell things, so companies like Rip Curl have to sponsor athletes who will get the most eyes on their brand.

But increasingly, people like Moore are showing that sex isn't the only thing that sells. Carlo Cavallone, executive creative director of the ad agency 72andsunny, told HuffPost that the existing model "comes from the misconception that the ultimate audience for sports is low-brow males who, ultimately, don't care about what women can really bring to the sport."

In an ad for Samsung's ongoing sponsorship of the WSL, his agency decided to focus on the deep cultural bond that surfing instills in those who love it, rather than trying once again to sell sex to the audience. The video, released last summer, featured a diverse community of surfers, including a group of smiling female friends in hijabs, headed for the water, boards under their arms.

It was a breath of fresh air, especially when compared to a viral 2013 Roxy ad that featured a faceless woman (actually five-time world champion Stephanie Gilmore) undressing and showering before the camera focused in on her butt as she paddled out in the ocean.

But there might be reasons for optimism hidden in YouTube view counts. As of Wednesday, the Samsung spot had received more than 5 million views on YouTube -- 3 million more than Roxy's butt-focused advertisement. Perhaps the depths and passion of surf culture is what really sells.