Mysterious deaths of hundreds and thousands of dolphins and birds along the shores of Peru in the past few months have raised concerns over mass deaths of animals happening every year along the coastlines around the world.

Peru's government declared a health alert along its northern coastline after at least 5,000 birds and an estimated 900 dolphins have washed up dead on Peru's northern Pacific coastline in recent weeks.

While investigations into the cause of the deaths are on, the government has urged residents and tourists to stay away from a 70 km (40 miles) stretch of the shore between the northern provinces of Lambayeque and Piura.

The National Agrarian Health Service of Peru (SENASA) has declined to speculate about the impact of avian influenza virus on human health or any outbreak of Newcastle disease in poultry because of the birds' death.

According to the ministry of agriculture of Peru, over 5,000 birds, including pelicans and boobies have died on shores between Punta Negra (Piura) and the inlet of San José (Lambayeque) beaches. Despite rigorous investigations, the unexplained deaths of the animals have baffled scientists.

Most of the dolphin deaths in the past few months were reported on Pimentel beach in Chiclayo and at San Jose beach, 40kms north of Chiclayo. The cause of the dolphins' deaths also is still being investigated.

Peru's Oceanic Institute (IMARPE) said that they had also found the carcasses of five sea lions that washed ashore and the decomposed remains of a turtle in the past week between Lambayeque and Piura.

Jose Delgado Castro, Technical Manager of the Technical Administration of Forestry and Wildlife (ATFFS) of Lambayeque Department of Agriculture (MINAG), said they took the samples from sea water and sand to check for possible contamination, but the actual reasons and the origin of the deaths are still unknown.

He added that it was needless to alarm the population about health hazards from the death of birds until the origin of death is scientifically determined.

A few pictures here show the plight of dolphins and birds dying on shores of Peru:

A dead Guanay Cormorant bird lies on Cerro Azul beach in Canete, Lima May 6, 2012.REUTERS/Mariana Bazo
Dead pelicans are displayed by conservationists at Reventazon beach, close to the Illescas peninsula in Piura April 27, 2012.REUTERS/STRINGER Peru
Dolphin carcasses are seen after being displayed by conservationists and environmental police officers at San Jose beach, 40kms north of Chiclayo April 6, 2012. The cause of death of over 900 dolphins in the last four months on the shores of Piura and Lambayeque is still being researched.REUTERS/Stringer
A dead pelican lies on the shore of the Villa beach in Lima, May 8, 2012.REUTERS/Pilar Olivares
Dead pelicans are seen at Reventazon beach, close to the Illescas peninsula in Piura April 27, 2012.REUTERS
A dead pelican lies on Cerro Azul beach in Canete, Lima May 6, 2012.REUTERS/Mariana Bazo
A resident feeds a Guanay Cormorant bird along Cerro Azul beach in Canete, Lima May 6, 2012.REUTERS/Mariana Bazo
A dead pelican lies on the shore of the Villa beach in Lima, May 8, 2012.REUTERS/Pilar Olivares
A dead dolphin lies on Pimentel beach in Chiclayo, May 6, 2012.REUTERS
People sit near a dying pelican at Pimentel beach in Chiclayo, May 6, 2012.REUTERS
Dolphin carcasses are seen after being displayed by conservationists and environmental police officers at San Jose beach, 40kms north of Chiclayo April 6, 2012.REUTERS/Stringer .