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In the swampy wetlands of southern Mexico , officials and experts are struggling to explain the deaths of dozens of manatees , as well as ravens, fish, snakes , among other species.
The fishermen who navigate the muddy waters in the coast of Tabasco have discovered at least 28 dead West Indian manatees since May , also known as sea cows, along the Bitzal River and nearby streams.
The cause of the deaths remains a mystery . Locals report deaths of fish in the river and blame polluted water in an area near drilling projects operated by the national oil company, Pemex . The company says that tests show no pollution in the area.
Other scientists wonder if the deaths of the animals, which divide their time between the ocean and inland rivers, are related to climate changes and rising sea levels.
“Whenever you see a series of deaths like this one, it can be a canary in a coal mine,” said David Gonzalez-Socoloske , a tropical mammal ecologist at Andrews University, in Michigan.
“Beyond the concern for the species, it tells you that something is going on with the environment ,” he said.
Across the Gulf of Mexico, in Florida , 92 manatees have died since January within an area where the growth of microscopic algae has caused a “red tide,” according to the Florida Fish and Wildlife Conservation Commission.
But the same type of seaweed, which only grows in seawater, cannot grow in Tabasco’s fresh water, where manatees have been perishing, said Ricardo Aguila r, from the Mexican wildlife advocacy group AZCARM . “The only relation is that the animals dying are manatees,” Aguilar said.
Desperate to prevent more deaths while they investigate the cause, wildlife authorities in Mexico have vowed to capture and transfer about 30 manatee s to a nearby nature reserve.
But capturing a manatee, which can weigh up to 1,100 pounds is difficult, said Leon Olivera-Gómez , a marine specialist at the Autonomous University of Tabasco and the rescue mission’s lead scientist.
Before the capture, Olivera-Gómez said scientists use sonar to locate the animal. Then, a group of around 20 people surround and trap it with large fishing nets.
So far, the scientists have caught two adults and a calf.
A VULNERABLE POPULATION
Olivera-Gómez
said that around 500 manatees , which are distantly related to elephants, are believed to live in Tabasco’s waters . The International Union for Nature Conservation, a leading wildlife conservation group, describes the population as vulnerable.
But past efforts carried out in Mexico to save threatened marine mammals have seen mixed results. Last year , in a bid to save the vaquita , a pint-sized porpoise that swims in the Gulf of California, two of the critically endangered animals were placed in a breeding program, but one died in captivity.
The deaths of manatees highlight the threat to the Gulf’s lowland wetlands , which have historically been defined by seasonal rains and dry spells that scientists say will become more extreme as global sea levels rise.
Climate swings
, Gonzalez-Socoloske added, can make animals like manatees less resilient to disease-causing pathogens.
Tests
around Macuspana and other waterways in Centla and Jonuta have not shown any oil spills , Pemex said in a statement on Tuesday.
Last month, Mexico’s water authority CONAGUA collected samples from the Bitzal lagoon and said the water did not contain high levels of oil , metals or pesticides that could explain the deaths.
However , Dennis Potenciano, the leader of the fishing cooperative in Macuspana , home to around 700 fishing families , said oil contamination has killed numerous fish and made the water undrinkable .
“The government doesn’t tell us anything ,” he said. “They treat us as if we are illiterate .”
“We aren’t catching anything because the river is so polluted ,” he said, on the grassy edge of a shallow waterway where he and others found 12 dead manatees.
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