By Jaylan Boyle, Senior Contributing Reporter

RIO DE JANEIRO – Anyone lacing up a pair of trainers with the intention of taking a jog around the Lagoa Rodrigo de Freitas probably got a nasty surprise this week. Nobody but the masked city municipal workers dared to get anywhere near the normally picturesque lake, situated in the heart of Zona Sul and adjacent to Rio’s most exclusive neighborhoods, Ipanema and Leblon, due to the stench of some 86 tons of dead fish that carpeted the lake’s shore and surface since the weekend.

Dead fish are turning bottoms up in the Lagoa Rodrigo de Freitas.
Dead fish are turning bottoms up in the Lagoa Rodrigo de Freitas.

It was left up to around 100 of the city’s Comlurb workers to deal with the mess, who must have been wondering whether some sort of extra recompense was in order, more accustomed as they are to sweeping the city streets. It took more than 48 hours to bring the lake back to even a semblance of normality, but officials will no doubt be relieved that the fish chose to wait for carnival to wind down before they died en masse.

An unusual and sudden proliferation of a type of algae is being officially blamed for the ecological disaster, which multiplied suddenly to catastrophic levels helped by ‘climatic variation’ in the preceding few days. The bloom of these algae may have starved other species in the lake of oxygen, according to officials from the State Institute for the Environment (INEA), who collected samples on-site for immediate analysis. The fact that fish were observed to be coming to the surface for oxygen proved that there was none in the water at the time, said INEA biologist Mario Moscatelli, who was quick to pour cold water over the hypothesis that global warming could have played a part.

According to Mr Moscatelli, the presence of sewage in the lake was due to problems with the lake’s outlet into the Atlantic sea, the canal of Jardim de Allah, which then caused the phenomenon, called efflorescence. Algae expert Mariângela Menezes said that samples of more than 400 per milliliter of the culprit micro-organisms were collected during the days leading up to the disaster, far above what would normally be expected.

Lagoa Rodrigo de Freitas, as seen from Jardim Botanico, photo by Rodrigo Soldon.

Comlurb confirmed that fish species affected included yellowtail, catfish, tilapia, sea bass, and baran (a type of bass). All species have now apparently stopped dying, but what the die-off means in terms of the lake’s fish stocks and their ability to recover to normal levels was not commented upon by any of the agencies involved. Thirty-five families fish in the lake and will have their livelihoods dashed for an indeterminate length of time if no reason is found.

The mass fish death has turned what was being pointed to as a win for the city into something of a setback: last year it was claimed that the lake was finally fit for swimmers after a concerted clean-up program began to show results late last year.


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