Critically low oxygen levels in the water of the Alcantarilha creek near Armação de Pêra, caused by extreme heat, are leading to the washing up of dozens of dead fish. The local council has been prompted to urgently prepare an operation to flush and replenish the waterway.
Silves Town Council, which counts Armação de Pêra within the borders of its municipality, has released a statement saying that it is working swiftly to remove dead fish from the body of water, after measurements carried out by municipal technicians and the Portuguese Environment Agency (APA) found oxygen levels in the water to be far below normal.
“The low flow of the Alcantarilha stream, combined with high temperatures and limited water circulation, has led to a sharp decline in the amount of oxygen available,” the municipality said. Measurements recorded levels of around 10%, compared with normal levels of approximately 90%.
With oxygen levels so low, “the water is no longer able to support fish life, while the death and decomposition of algae and other organic matter may also occur”, the municipality warned.
The council has already begun removing dead fish to minimise the smell, and other potential impacts caused by their decomposition. It is also gearing up to carry out an operation to renew the water in the stream as soon as authorisation is granted by the APA.
As part of the planned intervention, the municipality has made the necessary personnel and mechanical equipment available to temporarily open a channel between the stream and the sea. This would allow seawater to enter the waterway and help replenish its oxygen levels.
However, the operation can only be carried out at high tide, and is subject to approval of the decision from the APA, the council stressed.
Meanwhile, the APA is awaiting the results of microbiological tests carried out on the water before deciding whether to authorise the opening of the stream. The results are sometime expected today, 20th August.
“Silves Municipality has the necessary preventive measures and resources in place and is prepared to proceed with the intervention as soon as authorisation is granted and the required tidal conditions are met,” the council said.
Fish deaths in the Alcantarilha creek are a recurring problem in the area during the summer months, caused by reduced water flow, high temperatures, and the resulting drop in oxygen levels.
A similar incident occurred just over two years ago, in July 2024.
Source: Silves Council
Photo credit: Archive image
