In a statement paying tribute to the couple, they said: “We are grieving for our loved ones and all of those affected by the tragedy.
“We would like to express our sincere gratitude to the emergency services and everyone who helped tirelessly in this rescue operation.
“Our parents were incredible people and an inspiration to many, but first and foremost they were focused on and loved their family and spending time with their new grandchildren.
“Together for five decades, our only comfort is that they are still together now.
“This is an unimaginable grief to shoulder. Our only ask is that our family’s privacy is respected at this time.”
The couple were aboard the Bayesian superyacht which sank off the coast of Sicily earlier this week, along with technology mogul Mike Lynch.
Mr Bloomer was a boardroom veteran with a career in the finance sector spanning 50 years, while Ms Bloomer was a former psychotherapist described as a “brilliant champion for women’s health”.
Mr Bloomer’s working life took a turn when he appeared as a witness in Mr Lynch’s high-profile fraud case.
The 70-year-old was an experienced businessman and chairman at a number of top firms, including banking giant Morgan Stanley.
He embarked on a career in finance when he joined American accounting firm Arthur Andersen, where he worked for two decades and became a partner based in London.
That firm, which was once counted as one of the world’s biggest auditors, collapsed in the early 2000s, years after Mr Bloomer had moved on to what would be his most prominent role at insurance firm Prudential.
Mr Bloomer had joined as its finance director in 1995 and within five years took on the top job of group chief executive.
His leadership came at the turn of the millennium and was a turbulent time for the US finance sector, with the burst of the dotcom bubble sending shockwaves across the economy.
Mr Bloomer was credited with bolstering Prudential’s profits and sales, but came under pressure over a failed bid for insurance firm American General and the company’s decision to cut its dividend by 40% in 2003.
He left the company in 2005, before going on to take on a number of boardroom positions.
They included as chairman of Morgan Stanley International and insurance group Hiscox, roles he held at the point of his death.
Morgan Stanley chief executive Ted Pick said: “Jonathan’s leadership and experience helped the firm manage a period of complex change for our international businesses.
“He has been a friend and mentor to many and we will all greatly miss his wise counsel and spirit of kindness.”
Hiscox chief executive Aki Hussain added: “It was a privilege to have known Jonathan and to have benefited from his generosity and wisdom over the last year in his role as chair of Hiscox.
“His deep experience across our industry and in the broader business arena, combined with his personal values, made him both an excellent chair and a person I was proud to know and work with.
“His advice and support were immensely valuable to me, and he will be dearly missed.”
And investment platform Hargreaves Lansdown, where Mr Bloomer was previously a board director, added to the tributes.
“Jonathan was a giant in financial services, and we remember him fondly at Hargreaves Lansdown as someone who made a major impact on the business with his wealth of experience when he served on the board from 2006-2013 including as our senior independent director,” the firm said.
“We in the Hargreaves Lansdown family will miss him and our thoughts go out to his loved ones, as well as those of the others lost in this awful disaster.”
The City veteran was said to have interests in sailing, rugby and music, and was also a member of the finance committee of UK children’s charity NSPCC.
He was married to Ms Bloomer, a trustee and long-time supporter of gynaecological cancer research charity the Eve Appeal.
Athena Lamnisos, chief executive of the Eve Appeal, called her “our very dear friend”.
For more than 20 years, she was a supporter of the appeal, both as trustee and committee member, the charity said.
The appeal added that she was a “champion for women’s health, medical research and all that the Eve Appeal stands for”.
Ms Bloomer was educated at Homerton College, Cambridge, where she studied English language and literature, and started her career as a teacher.
She later worked as a psychotherapist for nearly 30 years, specialising in anxiety and stress.
She was also a former director of property developer Change Real Estate, a property firm in Bristol which was founded by Mr Bloomer.
Sally Bailey, a former chairwoman of charity Pilot Light, wrote that Ms Bloomer was a “wonderful friend” to the Eve Appeal, and “a kind and caring person”.
Mr Bloomer was an associate of Mr Lynch, the technology mogul acquitted in a historic lawsuit.
Mr Lynch had been charged with fraud and conspiracy leading up to the sale of his company, Autonomy, to US firm Hewlett Packard (HP) for £8.6 billion.
Mr Bloomer was among those to give evidence as a defence witness as part of the 13-year legal saga.
He was named in court records as a board member and chair of the audit committee of Autonomy, a role he held from 2010, and where he was responsible for overseeing the firm’s financial reporting and governance.
According to media reports, Mr Bloomer and Mr Lynch were close friends.
The Bloomers were on a trip on a superyacht off the coast of Italy with Mr Lynch, following his court victory in June.