just a short journey west from the lagoa de itaipú, the larger lagoa de piratininga has experienced many of the same changes as itaipú. the first of fifteen lagoons that stretch all the way to the municipality of cabo frio, lagoa de piratininga is a natural marvel that looks over the opening between the atlantic ocean and the guanabara bay.

the lagoon is widely regarded by environmentalists to be under threat from various stressors in the area, which have all contributed to its current demise. the initiation of these stressors can be traced back to the 1940's, as with the lagoa de itaipú, when the canal de camboatá was built to connect the two lagoons, draining the lagoa de piratininga of its water, and with it many of the natural ecosystems that occur there.

since the draining of the lagoon, and the building of the canal, the water volume of lagoa de piratininga has drastically fallen, which has had a number of severe consequences for the lagoon.