More than 400 dead dolphins were found in January on the Pacific Ocean shores of northern Peru where twice that number perished in the entire of 2012, authorities have said.

Authorities never made the reason for the passings in 2012. They are completing post-mortems on the most recent dolphins found in the Lambayeque district on the northern coast.

Expert Jaime de la Cruz of Peru's IMARPE marine life organisation said in regards to 220 dead dolphins were found in the most recent week of January alone, the rest throughout the past three weeks. Post-mortem outcomes were normal in two weeks.

De la Cruz apart from saying that the examination outcomes are normal in two weeks added that the tests will keep tabs on lungs, kidneys and livers.

Post-mortems of a portion of the more than 870 dolphins found in 2012 were uncertain. Hypothesis extended from biotoxins in the ocean to seismic testing to an obscure disease. Experts have however stated that they are concerned for what has happened and intend to find out the cause for such massive deaths. These need to be examined as something like this is not at all normal.