Last week, after raising the number of dead fish to 1,500 tons, Chile's National Fisheries and Aquaculture Service (Sernapesca) reported that 100% of salmonid mortality in the Reloncavi estuary, Los Lagos region, had been removed. At that time, the farms that had communicated the activation of the contingency plan for harmful algal blooms (HABs) were in both the Salmonid Concession Grouping (ACS) N°1 and N°2, but mortality was concentrated in two farms in ACS N°1. However, Sernapesca announced yesterday that mortality has spread and has reached two more farms in ACS N°2.
According to the information provided by the inspection body, in the Salmonid Concession Grouping Nº2, there are twenty-eight active farms with a total biomass of 49,727 tons. Of these, eleven - equivalent to almost 40% - have activated their HAB action plans and two have also activated their massive mortality action plans.
As of yesterday, Monday, November 27, the mortality recorded in the two affected centers - no data has been provided about the concession companies - is 913.5 tons, most of which have already been removed, as reported by Cristian Hudson, Regional Director of Sernapesca Los Lagos.
"As always, we have been supervising compliance with the contingency plans of the affected companies and the removal of the mortality that must be done by the companies themselves. The mortality is being removed in its entirety and 898.8 tons have already been taken to final disposal at processing plants," he said.
However, although contingency plans for both harmful algae and mortality appear to be in full compliance, the alert continues. "We will maintain vigilance in this and the surrounding ACS, as farms in these areas continue to report the presence of the microalgae and erratic fish behavior on a daily basis, which is a wake-up call for our service," Hudson said.
Harmful algal blooms are a natural phenomenon caused by multiple climatic and environmental factors, which generate a numerical increase of one or several species of microalgae in the water. The cause of this mass mortality event is specifically the microalgae Thalassiosira pseudonana. It acts by lodging in the gills of fish, causing internal damage and death by asphyxiation.
Sernapesca recalled once again that the microalgae affecting the Reloncavi estuary do not correspond to the so-called 'red tide'. It receives this name because it is a concentration of unicellular algae that produce a reddish color on the surface of the sea, these microorganisms produce toxins that accumulate in the organisms of mollusks and crustaceans and make their consumption dangerous. This is not currently the case in Chile, where neither bivalve mollusks nor other fish are affected.