Fisher’s breakout performance came at the London 2012 Paralympic Games, setting a world record in the women’s 200 metres individual medley SM11 event and winning four medals in all - one gold, two silvers and one bronze.

She then went on to set another world record at Rio 2016, winning gold in the women’s 100m backstroke S11.

"My dream goal as a nine-year-old was to represent New Zealand at the Paralympics," Fisher said.

"Competing in high-performance Para-swimming means relentless training which I’ve loved and wholeheartedly committed to.

"It also needs immaculate dedication and an internal spark to ensure every decision will have the best performance outcome.

"Racing at multiple Games, sharing the highs and lows with team-mates and gaining understanding of my mind and body has given me perspective on life that I never expected.

"I’m fully content with my swimming career.

"But eking hundredths of a second from a race isn’t enjoyable or satisfying anymore.

"I thrive on researching each component of a situation, so I’ve taken time in making sure stepping away from racing is the right decision.

"But I’ll always be a swimmer of some description.

"I think being around water, listening to the ambitions and challenges young people tell me of, exploring Aotearoa and what it means to be Kiwi will be constants throughout my life."

Fisher, who recently competed at the Swimming New Zealand Short Course Championships, was a key member of the New Zealand team that produced performances at Rio 2016 to ensure the country’s most successful Paralympic Games ever.

The team secured 21 medals through 12 individuals, amassing nine golds, five silvers and seven bronzes.

Overall, the team placed 13^th out of 159 on the medal table, its highest placing of all time, and defended its title of number one in the world for medals per capita won during London 2012.

Fisher’s stellar career began at the age of nine when she first took up competitive swimming in Upper Hutt.

She made her international debut in Australia in 2007 and this was followed by a plethora of World and Pan Pacific Championship medals.

The Wellington-based Paralympian, who has trained twice daily for more than 10 years, has also followed passions outside of the pool.

Fisher is well known for her work as an advocate around disability and environmental issues, and for her support of developing Para-swimmers and mentoring of youth with visual impairment and their families.

She is now a part-time volunteer and recreation coordinator at the Blind Foundation.

Distance study through Massey University in Palmerston North enabled her to earn a Bachelor of Arts degree supported by a High Performance Sport New Zealand Prime Minister’s Scholarship.

Fisher is currently undertaking postgraduate psychology papers and learning the language of Te Reo Māori, while she also enjoys community music and is a regular with the Glamaphones and Wellington Community Choir.

"We have been working with Mary for quite some time to support her with this difficult decision and seeking to assist Mary in looking at what comes next," Malcolm Humm, the high-performance director at Paralympics New Zealand, said.

"Mary is an incredible person and an amazing Paralympian.

"We thank Mary for all of her inspirational performances and ongoing professionalism both within and out of Para-swimming.

"We look forward to seeking ways of continuing to involve Mary within the Paralympic family and wish her all the best for her future endeavours."