Horrific images from the tragic scene showed the lifeless bodies of dolphins, turtles and even sea lions scattered across the shore.
In total the animal deaths included 21 dolphins, 11 turtles and four sea lions – all of which had died from a mystery condition.
Some had been washed ashore but others were simply floating in the water off the coast of western Mexico.
And bizarrely, none of the sea creatures appeared to have been marked or cut, meaning it was possible to rule out their deaths being linked to fisherman’s nets.
An in-depth investigation has now been called into place by concerned environmentalists who are now desperately trying to discover what caused the carnage.
The creatures were discovered across 26 miles of beach in the Gulf Islands, near the western state of Sinaloa.
Tourists have been warned not to use the beaches while the water is being tested for signs of pollution by Mexico’s Federal Environmental Protection Agency (FEPA).
A FEPA spokesman added that they were not expecting to discover the cause of the deaths for a number of weeks.
He said: “We will be looking at what species are affected, their condition, size, age, physical appearance, nutritional state, health, visible traumas, the time and date, climacteric conditions, state of the sea, topography of the beach and accessibility of the area.
“We will also be carrying out an autopsy and collecting samples of tissue and organs to conduct laboratory studies.”
However, at the moment there appears to be no obvious clue as to what led to their demise, he added.
READ MORE: http://www.express.co.uk/news/nature/612882/Marine-animals-dolphins-wash-ashore-beach-Mexico