Bo K.

UME’s, or unusual mortality events, are unexpected and unexplained beachings of countless numbers of marine mammals. These have effected many endangered species and greatly harmed the populations, like the stellar sea lion. They are associated with the increase of biotoxins and harmful algal blooms. The most prevalent biotoxin related with UME’s is domoic acid.

UME Related to Domoic Acid

Domoic acid is a biotoxin that affects many marine species, from shellfish to pinnipeds. Domoic acid is created by algae that are blooming in warmer oceanic waters, (temperatures have been raised by global warming). Warmer oceanic waters can cause algae blooms to produce domoic acid, poisoning the bloom, making the it harmful to any animal that eats the algae, like shellfish, anchovies, and sardines. The animals that eat those organisms, like otters and pinnipeds, also get infected as it seeps up the food chain. It acts like a neurotoxin, in that the symptoms of domoic acid poisoning in mammals (including humans) are memory loss, brain damage, and often, death. The increase in domoic acid can be traced back to global warming, a result from more greenhouse gasses, a result of higher emissions, from us.


As you can see, almost one half of the unusual mortality events have no explanation, which means we will have trouble preventing these in the future.

UME's have affected many marine mammals for many years. In fact, the number of these has increased steadily over the past twenty years. They primarily effect cetaceans, pinnipeds, manatees, and sea Otters. UME's are defined as "a stranding that is unexpected; involves a significant die-off of any marine mammal population; and demands immediate response" by the Marine Mammal Protection Act. The Marine Mammal UME Program was founded in 1991, and has 45 UME's on record as recognized by the government, from 1991 to 2008.
Lately, scientists are making more of an effort to examine carcasses and stranded animals that wash up on the beach as a result of UME's. This has increased the knowledge of explainable mortality events, which leads to better knowledge of the environmental stresses and population threats.

Domoic Acid Make Up

Pelican Affected by Domoic Acid

Domoic Acid Concentration Along the West Coast

UME’s and domoic acid are gripping threats to many marine mammal species. They cause mass wipe-outs of marine animals that are endangered or threatened, which could end in extinction.