The management of the sea lice in Chile: A review

Abstract Sea lice infestations have the largest economic and biological impact on salmon farming in Chile, similar to that seen in salmon‐producing countries in the northern hemisphere. Caligus teres infesting coho salmon ( Oncorhynchus kisutch ) was first recorded in 1981, but Caligus rogercresseyi has been the predominant species infesting Atlantic salmon ( Salmo salar ) and rainbow trout ( Oncorhynchus mykiss ) from 1997. In contrast, coho salmon has been shown to be resistant to this sea louse species. Regulations to establish integrated pest management of sea lice were implemented by the Chilean authority in 2007. However, to date, pharmacological medicines have been the main tool used by the salmon farming industry in Chile to manage sea lice, although non‐pharmacological treatments have been available since 2016. Production of farmed salmon reached 978.274 tons in 2021 and 7.72 g of medicines was prescribed per ton of harvested salmon. The highest volumes used in that year were Azamethiphos (47%) and hexaflumuron (45.5%), in addition to 5532 tons of hydrogen peroxide. This review updates the current management of sea lice in Chile and also summarizes the biological knowledge of this important parasite.