Chile Investigates Algal Bloom That Choked 6,000 Tons of Salmon

(Bloomberg) -- Chilean authorities are investigating possible breaches by salmon farms that may have led to one of the deadliest algal blooms in five years in the second-largest exporter.

So far, the bloom has killed more than 6,000 metric tons of fish kept in cages along southern Chilean fjords, said Cristobal De La Maza, who heads the environmental agency known as SMA. While that’s far less than the 40,000 tons lost in a 2016 bloom, there are indications it could have been contained better, he said.

“While it’s not a catastrophic magnitude like in 2016, it’s worrying,” De La Maza said in an interview. “We are investigating to see if there has been non-compliance.”

The bloom, typically the result of high concentrations of nutrients, is dimming output prospects for one of Chile’s biggest export industries. Salmon producers are just starting to recover from a slump in Chinese demand after Beijing raised concerns about Covid-19 risks in imported seafood, spooking consumers.

While there can be other contributing factors to the bloom -- such as lower rainfall, deforestation and wastewater from towns -- aquaculture is one of the main nutrient producers. Overproduction and leaving dead fish in the water too long can exacerbate the problem.

“We are investigating not only if they managed the mortalities adequately, but also if they complied with maximum limits of production that has to do with nutrient generation,” De La Maza said.

Possible Sanctions

If breaches are confirmed, sanctions will depend on the scope of environmental impacts and could include revoking licenses if damage is deemed serious enough, he said. Separately, the SMA is preparing sanctions for overproduction at some fattening centers in the area.

Chilean salmon farming grew exponentially in past decades only to run into sanitary issues such as a devastating outbreak of the ISA virus and the 2016 algal bloom. Rules have been tightened since then and will continue to be adjusted, De La Maza said. The SMA is working on a system of early alerts and is revising production limits in a bid to mitigate outbreaks that may become more intense and frequent due to climate change.

“With this event we’ve had in 2021, we have to continue perfecting rules and improving the environmental management of the whole aquaculture industry,” he said.

Ten farming centers have algal bloom contingency plans activated in the Los Lagos region, according to Chile’s fisheries and aquaculture agency. More than 4,500 tons of dead fish had been withdrawn from the zone as of Thursday.

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