Harmful algae blooms in southern Chile’s Los Lagos and Aysén regions have caused 5,282 metric tons (MT) of farmed salmon mortalities to date, the National Fisheries and Aquaculture Service (Sernapesca) reported on 11 April.
The die-off is equivalent to 3.4 percent of the total active biomass in the affected areas. A total of 18 farms – six in the Los Lagos region and 12 in the Aysén region – maintain action plans against mass mortalities. The mortality in Los Lagos is associated with the H. Akashiwo microalgae, while in Aysén, Leptocylindrus danicus and Leptocylindrus minimus have been detected.
Of the total mortality, 2,843 MT correspond to the affected farms in the Los Lagos region, which is equivalent to 11.8 percent of the active biomass in the concession areas affected, and 2,439 MT to those in the Aysén region, corresponding to 1.9 percent of the active biomass in the concession areas affected.
As of 10 April, some 4,301 MT, or 81 percent, of the total mortality had been removed (1,983 MT in Los Lagos and 2,318 MT in Aysén). Sernapesca has issued all the necessary authorizations for the prompt transfer – via fishing vessels, barges, wellboats and trucks – for the removal of the remaining 19 percent by the salmon farmers involved.
The fishing authority also greenlighted the transfer of live fish from farming centers that are in the affected areas to algae-free zones. In the Los Lagos region, 5,894,707 specimens have been moved and in the Aysén region, 348,750 fish have been moved. Another 1,331,435 fish are to be harvested. Early harvest and fish transfer are key preventive measures to mitigate risk in these types of events, Sernapesca said, adding that it would continue to monitor the situation in conjunction with related sectoral authorities.
Sernapesca also noted that in the Aysén region, three centers officially ended their contingency plans, and additional five farms decreased mortality levels to what is considered “low,” and will be able to end contingency actions as long as environmental conditions do not change.
In early March, Sernapesca reported an increase in mortality at Camanchaca’s Nieves farm in the Reñihue Fjord, in the Los Lagos region, due to low oxygen levels caused by a microalgae bloom. Since then, several farmers in Los Lagos and Aysén have activated contingency plans due to mass mortality, mainly due to low oxygen levels and algal blooms.
Photo courtesy of Alexander Gold/Shutterstock
