Death of 11,000 migratory birds in Miankaleh Wetland “due to botulism toxin”

After examining various possibilities, the Iranian Veterinary Organization declared poisoning the cause of the death of thousands of migratory birds in the Miankaleh wetland. Mazandaran environmental officials had announced the cause of the birds' deaths as unknown about a month ago.

The death of migratory birds in the Miankaleh International Wetland is not a new issue, and there has been much speculation about its cause; from intentionality and poisoning of the wetland water by illegal fishermen to the outbreak of highly contagious bird flu.

The state-run IRNA news agency reported on Tuesday, March 9, citing the country's Veterinary Organization, that the cause of the death of thousands of migratory birds in the Miankaleh wetland was botulism poisoning.

The organization says that from the beginning of this year to March 1, more than 11,000 migratory birds have died in the Miankaleh Wetland, and after examining "all hypotheses" in reference laboratories and applied studies, it has been determined that these birds were poisoned with botulism toxin.

One way botulism toxin is produced in wetlands and stagnant waters is through bacterial interactions in plant species such as algae under conditions of severe oxygen depletion.

The country's Veterinary Organization says field research shows that 94 percent of the dead birds were pelicans, 3.5 percent were flamingos, and the rest were from 20 different species.

Emphasizing "100%" on botulism toxin and denying other causes

The report of this institution states that the study of "environmental factors, estimated time of onset of the event, species involved, age and sex of the birds involved, number of sick and dead birds, population at risk, characteristics of the incident site, as well as analysis of field data collected from the incident site" shows that the main cause of the high mortality of birds in the Miankaleh wetland was 100% "heat-sensitive biotoxin (botulism)."

Ali Safar Makanali, head of the country's Veterinary Organization, emphasizes that the organization's latest tests show that the deaths of migratory birds in Miankaleh were not due to highly pathogenic avian influenza, Newcastle disease, or the presence of heavy metals, and that these cases have been ruled out.

According to IRNA, in 2019, more than 50,000 migratory birds died in the Miankaleh International Wetland due to what is said to be botulism poisoning. Accordingly, the number of migratory bird deaths in the first 11 months of this year was much lower than last year.

Doubts about the Veterinary Organization's theory

Despite the Veterinary Organization's emphasis on determining the definitive cause of death of the migratory birds, some experts and environmental activists accuse officials of covering up the real cause and consider botulism poisoning unlikely.

In an interview with the "Rokna" website in May of this year, environmental activist Ismail Kahrom, referring to the history of illegal hunters dumping poison in the wetland, said that officials are "solving and covering up the issue" under the pretext of botulism toxin in order to avoid being brought to the attention of the police, the public, and the courts.

Homayoun Khoshrovan, the executive of the international project to study the impact of Caspian Sea fluctuations on the environment of coastal areas, told the "Aftab" website at the time that, given the fundamental difference in the habitats of flamingos and storks, it is not plausible that both species are susceptible to botulism poisoning.

Khoshrovan said: "In the flamingo habitat, there is no algae that would die, become keratinized, or have its shell destroyed and produce botulism toxin."

This expert does not believe that poisoning the water is the cause of the death of migratory birds, and says that if this hypothesis is correct, we should also witness a severe loss of aquatic life, which has not occurred on a large scale this year.

One of the problems that most environmental activists agree on is the role of influential institutions and individuals encroaching on protected areas, changing land use and implementing incorrect policies, and ignoring the requirements for protecting such areas.

One of the manifestations of the ineffectiveness of government policies in environmental protection is the drying up of Gorgan Bay in Golestan Province. This bay and the Miankaleh Wetland were registered as international protected areas in 1975.

Source: DW