Culprit in Mysterious NM Elk Deaths Found

A hunter stumbled upon a bizarre sight on a 75,000-acre ranch north of Las Vegas, N.M., on Aug. 27: the remains of more than 100 dead elk. Livestock deaths are not unusual, but so many animals dying off, and doing so in what seems to be under 24 hours, was puzzling to scientists. Officials with the New Mexico Department of Game and Fish investigated the mysterious elk deaths and ruled out several possible causes for the elk deaths, including poachers, anthrax, lightning strikes, epizootic hemorrhagic disease (an often-fatal virus known to affect deer and other ruminants), botulism, poisonous plants, malicious poisoning and even some sort of industrial or agricultural accident. "We couldn't find anything [toxic] in their stomachs and no toxic plants on the landscape," said Kerry Mower, a wildlife disease specialist with New Mexico Department of Game and Fish, as quoted by the Santa Fe New Mexican newspaper.  Through science and further testing of elk tissue samples and water samples, the real killer has finally been found: pond scum. Or, more specifically, a neurotoxin produced by one type of blue-green algae that can develop in warm, standing water. A bloom of this alga can be devastating to wildlife. "In warm weather, blooms of blue-green algae are not uncommon in farm ponds in temperate regions, particularly ponds enriched with fertilizer," according to a classic toxicology reference book, "Casarett and Doull's Toxicology: The Basic Science of Poisons" (McGraw-Hill Professional, 2013). "Under these conditions, one species of alga, Anabaena flos-aquae, produces a neurotoxin, anatoxin-A, which depolarizes and blocks acetylcholine receptors, causing death in animals that drink the pond water. The lethal effects develop rapidly, with death in minutes to hours from respiratory arrest." In other words, the elk herd suffocated to death, unable to breathe...more