Mexico’s environmental authorities found 137 dead, beached sea lions along a stretch of Pacific coast on the Baja California Peninsula .
Mexico’s office for environmental protection ( PROFEPA ) said in a statement that the sea lions did not show signs of injuries from getting caught up in fishing nets or lines, nor were there marks on their bodies from possible collisions with boats. Those are common causes for sea lion deaths or injuries.
The government department said authorities received a report about the sea lions on September 4 and started a search. The bodies were found along a 130-kilometer stretch of coast in the area of Comondu, in Baja California Sur.
The PROFEPA collected tissue samples from some of the bodies for further analysis, to try to determine why they died.
California sea lions are a protected species in Mexico but are not considered in danger of extinction there.
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According to the San Diego Zoo, sea lions, seals, and walruses are in a scientific group of animals called pinnipeds, which means "wing foot" or "feather foot." In total, there are six different species of sea lions.
Sea lions and seals are marine mammals that spend a good part of each day in the ocean to find their food. They all have flippers at the end of their limbs to help them swim. Like all marine mammals, they have a thick layer of blubber to keep them warm in the chilly ocean.
Until recently, sea lions were “hunted for their meat, skin, and oil.” The Zoo adds that “Steller’s sea lions are endangered, possibly due to the effects of commercial fisheries on their prey species. “They were also accidentally killed when caught in commercial fishing nets and were shot on purpose by fishermen who believed the sea lions damage their nets. Protective zones and other measures around known Steller’s sea lion rookeries have been implemented. Other sea lion species are experiencing declines as well, for many of the same reasons.
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There were over 700 strandings of young sea lions from Washington State to Baja California, Mexico, in 2013, an indication that something unusual is going on in the ocean. Young sea lions typically leave their mother and go out on their own between eight months and one year of age, but if they are weaned early or orphaned, they may not have learned the skills needed to hunt for fish on their own. Scientists are looking at what role pollution may play in these strandings.
Furthermore, “a neurotoxin called domoic acid is produced by algae during algae blooms and is called a red tide. Fish eat the algae, and sea lions and other marine animals eat the fish. High levels of domoic acid can lead to lethargy, seizures, and death. And pollution may have a significant role in more of these toxic algae blooms occurring. That’s why it’s so important to keep pollution and trash out of the ocean and to recycle plastic. There is a correlation between NOT recycling and the emergence of excess domoic acid in marine animals, a documented connection between animal populations and pollution .”
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