Peru is currently investigating the cause of the deaths of 500 sea lions that were found on the northern coast on Sunday. 

A local governor alleged that the sea lions were purposely poisoned because they were feeding on the seafood and scallops owned by fishermen. The Peruvian authorities are also looking at other possibilities, such as disease and accidental ingestion of plastic materials, according to BBC News.

The rotting bodies were discovered 400 kilometers north of Lima. City workers immediately removed them on the site due to health concerns, Discovery News reported.

This latest incident is not the first that sea animals were found dead on the coast of Peru, and the growing incidents of massive deaths of marine animals are causing the government to become "deeply worried."

In April, 500 pelicans, 54 boobies, some sea lions and a turtle were also found dead 70 kilometers away from the same coast. Initial investigation showed that the animals died along the shore.

A month later, 30 dolphins were found dead with broken ears and damaged organs. Environmental group Orca claimed that the dolphins died because of the explosions used in oil exploration, which Peruvian Fisheries Minister Gladys Triveno refuted, and said that their investigation found that the animals died of natural causes.

Another case was reported in October involving 117 seals in northwestern Peru that could have died of starvation. Then in early November, the authorities documented an additional 187 sea lions, some dolphins, sea turtles and pelicans.

The Peruvian government is expecting more similar cases in the next few months.

"If you look at the last two years, and there was a high and abnormal number of strandings in summer, between the months of February and March, and it did the same in the year 2014, but assume that this phenomenon was ahead, as it should occur in the first months of 2015," Aldo Aguirre, the head of the Illescas nature reserve in northwestern Peru, said to RT News.