SANTIAGO, June 20 (Reuters) - Chile's government said on Monday that it is putting in place stricter regulations for salmon farmers to combat wide-spread infections that have killed millions of fish and caused hefty financial losses for companies in recent years.
The regulatory changes are aimed at having salmon farmers in Chile, the world's second-biggest salmon producer after Norway, reduce the density of fish in pens and space farms further apart.
"This is a set of very complex measures aimed at taking care of the health of our (salmon industry)," Raul Sunico, the undersecretary for the Chilean government's Subpesca fishing and aquaculture body, told reporters.
Regulators will also require fish pens to be certified so as to avoid salmon from escaping. Escaped salmon have wreaked havoc in Chile's rivers, as the ravenous fish eat most of the native fish population.
The coastal waters are awash with a bacteria known as SRS, or Piscirickettsiosis. The bacteria causes lesions and hemorrhaging in infected fish, and swells their kidneys and spleens, eventually killing them.
Unable to find an effective vaccine to treat the virulent and pervasive bacteria, salmon producers have been using record amounts of antibiotics in recent years, driving away some U.S. retailers. They intensified their usage of antibiotics in 2015 from the previous year, government statistics showed earlier this month.
In 2007, the ISA virus devastated Chile's farmed-salmon industry, killing more than half of all fish.
Chilean companies AquaChile, Blumar, Camanchaca, Australis Seafoods, Multiexport Foods, Invermar, and the local unit of Norway's Marine Harvest have salmon farming operations in the nation. (Reporting by Anthony Esposito & Felipe Iturrieta; Editing by Alan Crosby)