Although still awaiting approval, Bird flu Highly pathogenic H5N1 would be the most likely cause of the disease. The extraordinary mortality rate of elephant seals (Mirounga leonina) This phenomenon, recorded this October on the Valdés Peninsula (Argentina), surprised scientists due to the dimensions it reached.
Environmental organization WCS Argentina has presented a report titled ‘Excessive Mortality of Southern Elephant Seal Calves in the Valdés Peninsula Attributable to Highly Pathogenic Avian Influenza H5N1’, which shows an alarming decline in the population count of southern elephant seals. The University of California-Davis and the Central National University of Buenos Aires also participated in the study.
The study was carried out in strategic sectors of Peninsula Valdés. The important breeding area of this species is All showed excess mortality in offspring likely infected with the HPAI H5N1 virus in the first half of October 2023.
Given this situation, the authors of the report make a number of recommendations to the public: Preventive measures to minimize the potential do not infect people.
“Calf deaths always occur during the seal breeding season. Remains at values below 1% (a result that has been recorded and remained constant for decades). However, this year recorded excess mortality rates ranging from 56% to 74%, depending on the region monitored.”, details the report carried out by professionals from WCS Argentina and veterinary experts from the above-mentioned universities.
1,300 dead calves
Fernando Bersano, director of the Wild Flora and Fauna of Chubut (the province where this region is located), confirmed to the MDZ portal that it is “on the coast of the province” More than 1,300 seal pups killed by bird flu countedand said it was undoubtedly “the highest number of deaths since records have been kept.”
“We knew about this phenomenon because corpses were observed in the survey along the Atlantic coast, but since the monitoring has been completed and all statistics have been examined, we can now give the figure” about the population settled around the Valdés Peninsula.
There are on the shores of Chubut Largest seal population in South America Its colonies are located around the Valdés Peninsula and slightly further south, to the area known as the “Hidden Island” between the mouth of the Chubut River and Punta Tombo.
Effect on other species
The document also revealed: high calf mortality rate An unusually large number of dead adults and subadults of varying sizes and stages of development were also observed, with a reduction of between 40% and 70% (depending on sector and sex) in the number of adult individuals on shores.
Demographic data of elephant groups were recorded during the census, but I found dead individuals of other speciesSuch as South American Tern, Royal Tern, Yellow-billed Tern, Swallow Tern, Kelp Gull and Fur Seal.
Although confirmation of laboratory results is awaited, a large number of affected individuals and some clinical symptoms are observed. sick animals HPAI suggests that the H5N1 virus may be responsible for the mortality rate recorded in elephant seals on the Valdés Peninsula.
The first mass deaths of elephant seals in the world
“This is the first record of mass mortality of southern elephant seals for this group, the species’ only continental species. First world record for mass death of elephant seals from bird flu If the diagnosis is confirmed,” the report’s authors warn.
counts seal population The operations, carried out in the south in different parts of the coast of the Valdés Peninsula, were carried out on 9, 10 and 12 October 2023. monitoring coastal and marine species WCS Argentina’s priorities.
It will be important to continue monitoring in the upcoming period. shedding season It will begin in November to record the impact of seals (sloughing) on categories of pups (currently at sea) and particularly on young females expected to breed next season.
“Next year, We will be able to measure the impact in September-October 2024 There was a devastating mortality rate of elephant seals in the Valdés Peninsula population. To do this, a new general census must be organized clearly and jointly with CONICET and the provincial authorities,” explained Valeria Falabella, director of the WCS Argentina Coastal Maritime Program.
“Today more than ever The importance of long-term monitoring of priority speciesIt is a work we have been developing at WCS Argentina since the 80s,” explains Falabella.
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Contact information of the Medo Environment department: Krizclimatica@prensaiberica.es
Source: Informacion
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