Australian investment heavyweight Tattarang Agrifood -- owned by mining magnate Andrew "Twiggy" Forrest -- has increased its stake in Huon Aquaculture to 18.51 percent, less than a week after meat-processing behemoth JBS made a $314 million offer for the salmon farmer in a bid to force the Brazilian group to commit to more sustainable practices.

Tattarang Agrifood first took a 7.33 percent stake in salmon farmer Huon Aquaculture by snapping up just more than 8 million shares on June 17.