This site was made possible by the generous support of the American people through the United States Agency for International Development (USAID) Emerging Pandemic Threats PREDICT program.
Copyright 2012 IUCN SSC Wildlife Health Specialist Group
Commissioned by the IUCN Species Survival Commission to serve as a first response for wildlife health concerns across the world.
Dolphin mortality has been reported along the Northern Peruvian coast (over roughly a 200km area around Tumbes, Piura, Lambayeque and La Libertad regions) since January 2012. Species affected are Delphinus capensis and Phocoena spinipinnis. Isolated reports also mention Tursiops truncatus.
Estimates of the extent of the die-offs have varied widely, from a few hundred dolphin deaths reported to over 3,000. The Peruvian Institute of the Sea (IMARPE, at the Ministry of Production) reported 877 dolphins carcasses counted along 178km of the coast, from Piura to La Libertad on the first week of April 2012. Most of these carcasses (73%) were in advanced decomposition, thus stranding of these animals was estimated to have occurred on the previous 4 months by IMARPE.
Forty two dolphin carcasses were examined at the field by IMARPE but only two fresh carcasses were submitted and necropsied at Cayetano Heredia University (UPCH) resulting in a limited sample collection.
The die-offs have sparked widespread speculation about the causes, but none have been scientifically confirmed. Necropsy analysis showed no signs of starvation, respiratory, digestive or neurological disease. While dolphin morbillivirus, a viral agent that has been found as a cause of dolphin mortalities elsewhere in the past, was at one point suspected in the dolphin die-off, there was no evidence of respiratory or neurological disorders that can be considered indicative of morbillivirus on the carcasses examined during this mortality event. Laboratory analyses of samples obtained from 2 animals resulted negative for Morbilivirus, Leptospirosis and Brucellosis, as well as toxicity from algal bloom, chemicals (carbamates and organoclorines) or heavy metals (copper, lead and cadmium).
Peru has also experienced avian die-offs this autumn along its northern coast. Pelicans (Pelecanus thagus) have been the most affected species, followed by the Peruvian booby (Sula variegata) and cormorants (Phalacrocorax bouganvillii). The National Service of Animal Health (SENASA at Ministry of Agriculture) collected and analyzed pelican and booby samples at the 4 affected regions: Piura, Tumbes, Lambayeque and La Libertad and reported the finding of Pasteurella multocida. All animals sampled were negative for Avian Influenza, Newcastle Disease and Avian Mycoplasma.
A large pelican die-off event occurred in 1997 following El Niño, which caused declines of anchovies, a primary food source for pelicans. Starvation is suspected in this year’s avian die-offs as well, with air and sea temperature warming effects implicated this past year from El Niño.
A governmental technical working group was formed to analyze the case, which concluded that there is no anthropogenic influence on the occurrence of these events. Several local and international NGOs have also expressed concern and offered assistance in the investigation. Currently, there is a working group for the establishment of the Peruvian Stranding Network lead by the Directorate of Biodiversity (Ministry of Environment) with the participation of representatives of Peruvian government, universities and NGOs. A presidential executive order for the creation of the Stranding Network is expected to be released by early September.
On August 7th , a new stranding of up to 60 sea lions on Puerto Pizarro, Tumbes was announced by the media. A quick response of the government supported by local NGOs confirmed the presence of only 12 carcasses; samples were collected by IMARPE and are currently under analysis.
The IUCN, through its strong network of regional wildlife experts, is monitoring the Peruvian dolphin and avian die-offs along with the efforts of Peruvian authorities and other international experts and NGOs. The IUCN stresses the importance of a thorough science-based investigation in assessing the scale, cause and appropriate response in a mortality event.
Submitted by the IUCN SSC Wildlife Health Specialist Group, with special thanks to WHSG members Dra. Patricia Mendoza, Dra. Marcela Uhart and Dra. Gulland.