According to a new study, the strandings of the furry creatures observed on the west coast may be the result of sea lions being exposed to dangerous levels of brain-damaging neurotoxin that can make them confused while irreversibly affecting their memory.

Although the neurotoxin is not directly created by man, humans may have something to do with it. Researchers explained that domoic acid is released by algal blooms that flourish in warming waters. So, sea lions do not just starve because high sea temperatures destroyed their prey’s habitats, but they also are at risk of having their brain damaged by the dangerous toxin.

During their study, scientists monitored a sea lion to see if its memory was somehow affected. The result of the study showed that domoic acid may be to blame for the dozens of sea lions and pups that seemingly have a poor spatial memory.

Nevertheless, the research team said that the findings were no news. They have suspected that the neurotoxin may affect the marine creatures since the 1990s. Peter Cook, lead author of the study, started to keep an eye on the toxin and its effects on the marine creatures nearly 10 years ago.

He explained that brain damage caused by domoic acid is easily recognizable – it mainly affects the creature’s hippocampus, while other neurotoxins can affect the entire brain. Humans exposed to high levels of domoic acid develop a disease called amnesiac shellfish poisoning.

Researchers said that there is almost no research on the effects of the neurotoxin on sea mammals because people often underestimated its large-scale impact on big groups of animals.

Cook’s team based their study on data they collected while working with stranded sea lions. Study investigators monitored their behavior, tested their ability to move in space, and scanned their brains to see whether their hippocampus was damaged.

Study authors said that they found many sea lions with brain lesions in the hippocampus, a very important area of the brain linked to the memory. Some of the animals had no lesions, others had superficial lesions, while other animals had severe brain damage in the hippocampus. The team noticed that the latter group was unable to retain any spatial information.

Staffers at the Marine Mammal Center that rescue stranded sea lions recall that they have seen some bizarre behaviors in the furry mammals as of recently. For instance, they found stranded animals in out-of-the-ordinary locations such as in the middle of a town, or on fields.
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