No one knows exactly what is causing the loss of so many sea birds and dolphins in Peru, but testing by the oil industry, a disruption in the food chain or a virus have all put been put forth as possible explanations.
Adding to the confusion is the fact different figures have been reported. One story says over 1,200 pelicans died, but another says the total is closer to 600. About 54 Peruvian Boobies also were found deceased. These birds were found in the same coastal area where many dolphins were also found lifeless in April.
Morbillivirus is being investigated as a possible cause, because it can result in the deaths of many animals. This type of virus killed many canines in Europe about 200 years ago in the form of canine distemper. Morbilliviruses have caused large die-offs of marine mammals in the past.
In the late 1980s a large loss of bottlenose dolphins on the U.S. Atlantic coast was believed to be related to a morbillivirus. In 1990 a large number of striped dolphins in the Mediterranean also were thought to have died due to infection from the same type of virus. In each of these events thousands of dolphins may have died. One confounding factor is simply that though many deceased marine mammals can be counted on beaches, there could be many more never observed, so there is not complete information.
Some people have expressed concern that the virus killing a large number of animals could mutate and infect humans, though this possibility is extremely small.
Image Credit: Jens Tobiska