A report from Chile's government says the amount of antibiotics used per ton of salmon has reached the highest level since 2007.

The country's salmon production has dropped as it battles outbreaks of a deadly fish disease, salmonid rickettsial septicemia. Farmers are using more antibiotics to combat the disease.

But demand for antibiotic-free fish among American consumers has spiked amid fears of antibiotic-resistant "superbugs." Last year, Costco stopped buying salmon from Chile and switched to Norway, where farmers use less antibiotics.

Chile's report comes a little more than a week after an environmental group won a lawsuit demanding more transparency about antibiotics use in salmon.

This year, Chile's salmon farming industry has also been hit with red tide algae blooms, which killed off 15 percent of the country's fish stocks and caused $800 million in losses.

Read More:

• Chile's Embattled Salmon Industry Intensified Antibiotic Use In 2015: Government (Reuters)
• Chile's Salmon Industry Using Record Levels of Antibiotics to Combat Bacterial Outbreak (EcoWatch)
• Toxic Algae Drive Up Insurance Costs For Chile's Salmon Farms (Financial Times)