Ellis was found unresponsive around 4.30pm by police officers at the Sir John Compton dam in Roseau, St Lucia, on Friday 16 August.
The 67-year-old was pronounced dead at the scene.
Joining Woolwich, south London-based Jamm in 2006, Ellis immediately played a key part in helping to establish a branch in Australia. He recently took a similar role in setting up the company’s European branch in Prague by overseeing the legal and financial details of running a business in the Czech Republic.
“When Martin joined us, he came with quite a lot of previous experience,” said Jamm managing director Liz Shackleton. “He had a lot of experience of the graphical trades, and of financial management and business development.
“Our team is quite close-knit, and people always felt they could go to him with questions and he was always there with advice and help. He had a very dry sense of humour.
“Martin was always prepared to take a risk if he thought it could benefit the company, and he was a planner. Quite visionary. He understood what it is like to work in a difficult industry at times when change is needed, and he was not afraid of change.”
Ellis came to the commercial, trade and direct mail printing outfit from a storied career, having worked for the National Gallery as a project director and also as general manager of photographic agency Corbis UK, which was founded by Bill Gates.
At Jamm, he always worked three days a week in order to be present for his three sons, who were on holiday with him at the time of his death.
He is yet to be returned to the UK and a cause of death has not yet been confirmed.
Ellis is survived by his sons and his wife Amy. Details for service and tributes will be made available at a later date.