Toxic algae responsible for brain damage in sea lions

Findings of a new study are suggesting that a toxin secreted by marine algae can cause memory loss in sea lions and make finding their way to food difficult. According to the said study, large blooms of the toxic algae off the Californian coast have possibly contributed to the record number of starved sea lions which have been found dead on the beaches of the state since 2013.

Here, it must be mentioned that the scientists have added that the algal toxin is not only harming the sea lions, but also a large number of other marine animals such as sea otters, dolphins, and fur seals. This problem is unlikely to subside anytime soon, mainly because nutrient-rich agricultural overspill and increasing temperature of ocean waters appear to be fueling algal outbreaks.

Peter Cook, a scientist representing the Emory University, said that the algal blooms will only get bigger in the coming months, and the current sufferings of the sea lions only mark the tip of the iceberg. Cook, who recently reported domoic acid’s behavioral effects at a conference of the Society of Marine Mammalogy, said that the future looks to be really grim of these marine animals.

Since 1998, scientists have been saying that domoic acid, the toxic substance produced by marine algae, causes a range of neurological problems including seizures in Zalophus californianus or the California sea lions. They have also been saying that high levels of the toxin can even kill the animals. However, so far the scientists only had access to anecdotal evidence suggesting that the chemical affects behavior.

Shawn Johnson, a veterinary scientist at the Marine Mammal Center, informed that previously scientists noticed sea lions showcasing odd behaviors, for instance, swimming up the rivers and entering cities and interacting with humans. John is excited to see that finally science has validated what people like him was aware of since a long time.

To confirm the effects of the algal toxin on sea lions, researchers studied the activities of 30 sea lions. The participating animals were made to complete a couple of memory and learning tasks. The results of the study showed that the ones with domoic acid poisoning faced difficulties when trying to complete a short-term memory task that required them to navigate through mazes for finding fishy rewards.