Šantić gained initial success in tuna fishing, having grown up in Port Lincoln. His early exploits in the fishing industry also included fishing for orange roughy in a leaky boat called the Vigorous off the coast of Tasmania. He went on to establish Tony's Tuna International in 1994.
In the early 1990s, Šantić suffered financial hardship after tuna quotas were reduced twice. The tuna industry and a number of related businesses suffered while others shut down entirely. Santic's business survived and by 1996, it had grown to include ranching operations in Mexico, the Mediterranean and Port Lincoln. The development of tuna ranching turned the tuna industry around and Tony's Tuna International became one of the three largest tuna ranching operations in Port Lincoln.
In 1997, Šantić decided to pursue his interest in horse racing, which ultimately led to three Melbourne Cup victories courtesy of a horse he named Makybe Diva. Šantić featured in the BRW Rich List in 2003, with an estimated personal wealth of $200 million. Fellow Port Lincoln tuna ranchers Sam Sarin and Hagen Stehr also featured on the list.
In January 2010, an ammonia cylinder exploded at Šantić's tuna processing facility, destroying a shed and releasing ammonia gas into the atmosphere. No-one was injured during the explosion and Šantić was out fishing at the time of the event. Safework SA announced that they would investigate the incident.
In 2012, Tony's Tuna International initiated plans to trial an alternative ranching regime involving the capture of younger, smaller fish, and extending ranching time from 6 months to 18 months. The initiative planned to make better use of the quota system, which allocates a total allowable catch to license holders, measured in tonnes. Later that year, Šantić and his wife Deslee became victims of fraud. The newspaper The Advertiser was informed that $700,000 had been siphoned out of their business interests and that a 33-year-old Torquay man was under police investigation. As of 2015, Šantić remains the CEO of Tony's Tuna International.
Oceanic Victor Pty Ltd
In 2015, South Australian Environment minister Ian Hunter revealed that Šantić was a director of Oceanic Victor Pty Ltd, a company with an active business proposal for Granite Island. With fellow director Michael "Mick" Dyer (who is also Tony's Tuna International's Operations Manager) and long-term friend and advisor Emma Forster, the company intends to offer offshore marine tourism opportunities for visitors to the Victor Harbor area. The company intends to use the kiosk at Granite Island as a departure point, from which tourists will be taken by boat to an offshore facility when they will be able to feed fish, swim with fish, and watch them from and underwater observatory.
He came to Australia with his family in 1958, aged six. His parents settled in Geelong, Victoria for the next 8 years before Tony and his mother moved to Port Lincoln, South Australia. He has three children, Emily Šantić (born to his first wife, Sonya) and Joseph Šantić, born on 8 March 1989 to his second wife, Christine. Tony and Christine were together for 22 years and married in 1996, following the death of his first wife Sonya to Hodgkin's disease. The couple shared three Melbourne Cup victories together with their racehorse, Makybe Diva.On 25 April 2009, he married his third wife, Deslee Kennedy, and the couple had a child, Charli Rose in October that year.
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- "Two Tuna Farmers On Australia’s Super Rich List". atuna. 2003-05-22. Retrieved 2015-04-25.
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- "Higher Catches Of Baby Bluefin Should Boost Return Tuna Farms". The Advertiser. 2012-01-02. Retrieved 2015-04-25 – via atuna.
- Harris, Amelia; Buttler, Mark (2012-05-04). "Tycoon victim of massive swindle". The Advertiser. Retrieved 2015-04-25.
- "About Us". Tony's Tuna International. Retrieved 2015-04-24.
- "New Granite Island tourism proposal to allow swimming and hand feeding of fish". The Advertiser. 2015-04-23. Retrieved 2015-04-24.
- Nicholson, Rod (6 May 2007). "Šantić boys quit tuna firm". Sunday Herald Sun. Retrieved 2008-03-27.
- Warner, Michael (2008-12-06). "Tony Santic's wife used his Grange in the bolognaise". The Australian. Retrieved 2015-04-24.
- Byrne, Tony (2009-10-24). "Christine Santic: Life without Tony Santic". Herald Sun. Retrieved 2015-04-24.
- Wilson, Kim; Nicholson, Rod (2009-09-06). "Tony Santic believed to become a dad again to Deslee Kennedy". Sunday Herald Sun. Retrieved 2015-04-24.