Chilean salmon farmer Multi X says low oxygen levels in the water caused the mass mortality of 30,000 fish at its Quemada production site in the Aysen region of the South American nation.

"This mortality was produced due to environmental challenges, mainly low oxygen. Once the mortality started we activated all the protocols fulfilling the requirements of the authorities," Multi X CEO Cristian Swett Pla told IntraFish.

Nine cages were affected by mortality at the site, which housed 969,603 fish with an average weight of 4.7