Why are millions of dead fish appearing in rivers of different countries?

First modification: 03/19/2023 – 19:26

In Australia, citizens complain about the putrid smell coming from the river: “Ehe stench was terrible. I almost had to put on a mask,” local nature photographer Geoff Looney told the AP.

“I was worried about my own health. That water right at the top goes down to our pump station for the city. People north of Menindee say there’s cod and perch floating down the river everywhere,” he explained.

The mass death of the animals occurred in the Darling River, the second longest river in Australia, located about 1,000 km west of the state capital of Sydney. The fact was announced last Saturday.

It is not the first time that it has happened there, similar phenomena occurred at the end of 2018 and the beginning of 2019. Then it was known that millions of fish died due to lack of water flow, poor water and sudden changes in temperature, as reported at the time. local authorities.

On this occasion, the Department of Primary Industries stated that possibly the deaths of the fish were caused by low oxygen levels at a time when temperatures in the climate begin to rise, which means that the animals need more oxygen available. to survive.

Mass cleanup operations

Although since the middle of this week videos began to be released on social networks in which boats were seen making their way amid the great curtain of dead fish on the surface of the river, it was only until this Sunday, March 19, that the authorities announced the coordinated events that will be held for the cleanup.

New South Wales police said they have already set up an emergency operations center in Menindee to launch a massive cleanup next week.

“There is no need to worry about the community as the initial assessment has determined multiple viable solutions to maintain water supply to and around Menindee Township,” said Peter Thurtell., state controller of emergency operations.

According to Thurtell, the number one priority at the moment is providing a clean water supply to residents and working with state agencies to release higher quality water into the river to increase dissolved oxygen levels in the area.

Two more places with massive fish kills

This same week, tourists denounced Dozens of fish died off Lido Key Beach in Sarasota, Florida.

A season in which beach visitors are enjoying spring school vacations on these Florida coasts, a destination highly desired by thousands of Americans and foreigners.

As announced by the authorities, the death of the animals is due to the proliferation of the Karenia Brevis microalgae, a phenomenon that is recurrent in the area, but that this year came “at a bad time”, as announced in a statement by the Florida Department of Health.

“People get sick. Why would anyone want to spend a lot of money and stay here,” Jeff Napier, an employee at the Lido Beach Resort hotel, told AFP.

This very week, Hundreds of fish and various species of animals were found dead on the shores of the jamapabetween the municipalities of Ixhuatlán del Café and Tepatlaxco, Mexico.

In this case, the local authorities assured that the massive deaths are due to contamination in the river, since its waters are also used to irrigate the fields and for domestic use by the residents.

Also in Mexico, at the beginning of the month it was registered in local media in Puerto Vallarta, Jalisco, the monumental fish kill at Flamingos beach.

According to Civil Protection and Fire Department of Puerto Vallarta “the massive mortality is mainly due to two factors: number one due to the abrupt changes in temperature in the water and two, due to the growth of microalgae in the sea”, a phenomenon also known as red tide.

On January 17 of this year, videos of thousands of fish writhing in spasms on the shore of Yavaros Bay, in the municipality of Huatabampo, Sonora in northern Mexico, went viral.

Although at first the alleged presence of toxic agents in the water was pointed out, the Aquaculture Health Committee of the State of Sonoras (Cosaes) ruled out that hypothesis after it sent a technician to collect the samples. Some time later it was assumed that the red tide would have been to blame for the massive deaths of marine animals.

With AP, Reuters and local media.