split image of merle cleaning trash and holding monofin

It’s not often we catch a glimpse of a real-life mermaid, but in shellebration of World Ocean Day, the world got to sea one in action!

On 7 May 2022, onlookers watched on while Miami Eco Mermaid Merle Liivand made waves as she swam 42.2 km (26.22 miles) off the choppy waters of Miami Beach, Florida, USA, in just 11 hours and 54 minutes, breaking her own record for the farthest swim with a monofin.

The four-time record holder is more than just a competitive swimmer, she’s a marine conservationist and aquapreneur helping to save the sea. 

Originally from Tallinn, Estonia, Merle is an ice swimmer and former Baltic champion who relocated to Florida 11 years ago.

She spends her time training others to swim and raising awareness of the damage caused to our oceans.

What’s unique about the clean ocean advocate is that she regularly swims wearing a silicone mermaid fin without using her arms to increase endurance and generate publicity for the oceans.


Although Merle initially set the record for the farthest swim with a monofin on 17 April 2021, she mentioned that marine conditions during that record attempt weren’t ideal and that she knew she could swim much farther.

And so, on that sunny Saturday morning, the Miami Eco Mermaid slipped on her swim cap and Luna Fin, lathered herself in eco-friendly sunscreen, and set out from the Sunset Harbour Marina on a long, arduous swim around Biscayne Bay. 

But what first encouraged Merle to dive into this fintastic record attempt?

“I was born with auto-immune health problems, and I started swimming because my lungs collapsed,” she said. 

“Today, my intention is to fight for Mother Earth’s lungs.” 

Merle advocates against marine pollution and uses her long-distance open-water swims as a means to draw attention to the growing environmental issue of ocean pollution, which she refers to as a “plastdemia” or “plastic pandemic.”

During one of her practice swims, the Estonian professional swimmer recalled nearly ingesting microplastics while breathing. 

She felt that as an open water athlete, she should be doing more for the ocean rather than just swimming in it.


When Merle realized that plastic pollution was damaging marine life the same way it was affecting her during her swims, she challenged herself to swim exactly the way fish do. 

Instead of using her arms to propel her forward, Merle swam using only her legs and feet, bound in a custom engineered mermaid-like tail fin called a monofin.

“Swimming with the monofin without using my arms is similar to how dolphins and marine animals swim. They have a fin and can’t use any arms,” said Merle. 

“Using a fin sends the world a bigger message. It’s unfair that we have gotten to the point that fish, dolphins, and turtles are surrounded by plastic which ends up in their stomachs, and I feel that we as humans are next.”

Training like a mermaid

Although Merle is quite skilled when it comes to swimming and has made a big splash in the waters of the Bosporus and Golden Gate Straits, the Pacific Ocean, and the Baltic Sea, her swim around Biscayne Bay proved to be quite different. 

Being exposed to the sun can lead to overheating and exhaustion, particularly when exerted by attempting to swim such long distances.

Warm water increases internal body temperatures, which also raises sweat rates and accelerates dehydration. 

To prepare herself for her record attempt, Merle knew she couldn’t be a fish out of water. 

For over a year, she woke up at 4 AM every day and trained by exposing herself to the same conditions she knew she would face on the day of her swim.


Training in hot environments helped Merle elevate her heart rate and prepare herself both physically and mentally for what was to come.

“My last record was 30 km (18.6 miles) and Mother Earth really challenged me. I swam in very difficult conditions and knew that if I swam in the bay this time, there wouldn’t be a crazy current,” said Merle. 

“Over 13 months, I really changed my training. I planked for 50 minutes 3 times per week, attended hot yoga, focused on my breathing and nutrition, and connected with myself."

"It really inspired me to learn to be stronger and go against the current," continued Merle.

The open water champion also worked on her strength by using a parachute fabric to pull her training partners for miles with just the use of her monofin.

In the days leading up to her record attempt, Merle consumed between four and five thousand calories daily. 

She expressed that as a female athlete, it was necessary to remain hydrated and take magnesium and potassium pills to stave off leg cramps, which tend to be common during long swims.

“Figuring out my nutrition was always the hardest. You know that you have so many miles ahead of you, so I had to eat a lot to build up for this event,” said Merle. 

“I used over 11 thousand calories during the swim.”

Breaking her own monofin swim record

With her eyes on the prize, Merle never once stopped to eat during her record attempt. Instead, she consumed small meals that were easy to digest as she floated in the bay.

“I made sure to have smoothies, baby food, and soup. You can’t really eat anything heavy because you use your core a lot,” said Merle.

“Every time I would eat, I would have coconut oil because the conditions I was swimming in were salty and sunny, and if you eat salty food, your tongue can swell up.”


Humans dump about 8 million pounds of plastic trash into the ocean every year—an exorbitant figure which motivates Merle to continuously advocate for clean oceans.

Plastics that end up in ocean water often break apart into small pieces that cannot be seen by the naked eye. 

During her swim, Merle collected any garbage she came across, tossing it into the kayak rowing alongside her.

“When I see trash, I get angry,” said Merle. 

“I think about the manatees that are dying because there’s not enough seagrass for them to eat, or the kids who suffer because microplastics have affected their gut health."

"At the end of the day this isn’t just about a record, it’s about helping the community and the world," Merle added.


Although her efforts to clean up Biscayne Bay proved to be challenging, Merle says there were other parts of the arduous swim that were also very difficult. 

“I got stung by jellyfish and kept telling myself that it was not the time to cry,” she said. 

“The moments where I was feeling down, I had to remind myself that I’m a tool between the ocean and humans and I want my message to be heard.”

Though the Portuguese Man O’ War stings weren’t quite welcome, Merle had some company during her swim that certainly was. 

“I have a really special relationship with the dolphins, and I think they know I pick up trash. Every time I clean the bay, I see dolphin tails swimming by to say hi. I feel a connection between us,” said Merle. 

“I swam towards the rocks and saw a mother manatee and her two babies following me. I think animals know I fight for their environment and it’s a magical feeling.” 

With three mesh bags teeming with garbage, Merle completed her swim and waded back to her starting point at the Sunset Harbour Marina. 

Finishing off just as strong as she first started, she proudly added one more record to an already impressive list.

  • In 2019, Merle first set the record with a 10 km (6.2 miles) monofin swim off Redondo Beach, California (time: 2 hr 54 min). 
  • In 2020, she performed a 20.6 km (12.8 miles) monofin swim off South Point Park Pier in Miami Beach, Florida (time: 6 hr 8 min).
  • On 17 April 2021, Merle broke the record for the farthest swim with a monofin in Miami Beach, Florida (time: 9 hr 19 min).

Merle is optimistic that her latest record will serve as a lesson for the world and hopes that people will focus on reducing the production and consumption of plastics. 


“Humans should take a moment to understand that we need to use less plastic or make sure that we clean up any trash on the ground,” she said. 

“We need to make sure that we’re all healthy. Healthy humans mean a healthy planet.”