Sea lions could be developing a sort of dementia due to a toxic algae that scrambles their memory, making it difficult for them to find food. Researchers believe this could explain why sea lions lacking expected navigation skills have been observed in past years. Humans are partly to blame for this, as our impact on marine systems and global temperatures have helped the implicated algae blooms flourish.
Scientists have observed the disruption of memory in California sea lions, the reasons for which have been tied to domoic acid, DA for short. The neurotoxin is produced by algae blooms off the state’s coast, with both the size and number of blooms increasing yearly as the environment changes. When exposed to this neurotoxin, sea lions could have seizures and die.
Recently, researchers used MRIs to study the brains of sea lions exposed to domoic acid and found their hippocampal regions had “structural abnormalities,” including lesions in an area of the brain used to spatial memory. The more extensive the damage, the worse the affected sea lions performed in trained spatial memory tasks.
It isn’t clear whether domoic acid has a similar effect on other exposed wildlife. Researchers posit that assessing hippocampal regions of sea lions’ brains will aid researchers in determining whether a rehabilitated sea lion will be able to successfully reintegrate itself in its’ natural habitat.