The Acció Climàtica department will remove some two tons of fish a day in the coming weeks from the Sau reservoir to guarantee the water quality of the reservoir, which is currently at 10% of its capacity. In parallel, 0.5 cubic hectometres of water per day are being released from Sau to Susqueda.
The department's intention is to divert the maximum amount of water possible before fish mortality, which could begin to appear in a month if the high temperatures continue to end up contaminating the water in the reservoir, which is at the lowest level in recent decades. .
The reduction in Sau volumes may end up leading to a decrease in oxygen in the water, a fact that could also cause species mortality if they are maintained at high densities.
In order to save the maximum amount of water in the current situation of extreme drought, the operation that will allow the removal of fish, 80% of which are exotic invasive species that inhabit the Sau reservoir such as catfish, carpines or carp, began today. All of them will end up being sacrificed. Also the only species not typical of the Ter river basin, such as the Ebro catfish, also present in the dam.
An estimate made in 2005 put the amount of fish that can inhabit this large body of water at 45 tons. Today an electric fishing boat carried out the survey to find out the approximate number of current species that are estimated in the area, which could range between 45 and 60 tons.
The forecast of the Climate Action department is to remove approximately 1 and a half tons of fish per day through the use of various types of boats. In 2005, a similar operation removed a total of 16 tons, approximately one ton per day. The forecast of the technicians is to greatly exceed this figure.
If we do not proceed with this operation of removal of parts, the little water that remains in the Sau reservoir could end up contaminated and not suitable for oral consumption. The director of the Execution and Action Area of the Catalan Water Agency (ACA), Elisabet Mas, points out that the water currently stored in Sau represents the consumption of a million people over three months.
Guaranteeing supply to more than five million people in the Barcelona metropolitan region and the Girona region is the ultimate goal.
Today the boats that will be in charge of this process have begun to go down into the swamp, by means of a crane. There are two fishing boats from the Blanes brotherhood, which will remove the species with a system of nets, and two other pelican-type boats that will operate in shallower areas. There will be a fifth electric freckle boat, which would only operate in very small spaces.
The species will be treated by a company specialized in the treatment of biomass.
