The new entity will trade as Princes Tuna (Mauritius) and will be majority owned by Princes.
It will operate two processing sites and generate sales of around $400 million a year, said Princes.
“The new company’s scale will enable it to continue to drive long-term sustainability initiatives in the Indian Ocean region and strengthen its position in the global tuna market,” the group said in a press release.
It said contracts have been exchanged and the merger is expected to complete within the next few months.
“All employees will transfer to the new operation on completion.”
Thon des Mascareignes’ existing owners, including Ireland Blyth Limited (IBL) and the Mauritian State Investment Corporation, will have a stake in the new entity.
Founded in 2005, TDM is the second largest tuna processor in Mauritius after Sapmer, which has been enlarging its processing and coldstore operations in the Indian Ocean nation.
TDM’s tuna processing site in Mauritius produces loins for export to canneries and pouches for foodservice customers.
According to IBL’s first-half year report, TDM processes around 80 metric tons of fish daily in a value-added pouch format, with the balance sold as loins to the leading EU and US canners.
“The formation of the enlarged group cements Princes’ commitment to its operations in Mauritius and the Indian Ocean region,” said Princes.
Seafood and marine services make up around half of operations for the Mauritian conglomerate IBL, which also owns Froid des Mascareignes and Indigo Canning.
In March, IBL said the first half-year profit of the seafood and marine services segment had dropped down from MUR 3 million ($96,413) to MUR 2.97 ($95,499).
This was due to “deteriorating market conditions”, said IBL.
The company, which also owns the shipyard Chantier Naval de l’Ocean Indien and fishmeal business Marine Biotechnology Products, added that marine services had compensated the market effects to an extent.
In contrast, the marine and seafood business was IBL’s best performer during its 2013 financial year.
For that year, IBL’s seafood and marine segment reported a 66.6% increase in profit, to MUR 650 million ($20.8m), said IBL.
The segment was also the largest contributor to turnover in the year, contributing MUR 6.178bn ($198m), up from MUR 4.96bn ($159m) in 2012.