Algal blooms are causing the sea lions to damage their brains with a nasty toxin.
A new environmental crisis has emerged in California: sea lions that are being stranded are getting brain damage that can result in a condition similar to Alzheimer’s.
And the likely cause are algal blooms, which are not only harming the Dungeness crab supply along the Pacific Coast but are also sickening hundreds of sea lions with a toxin called domoic acid, according to a San Jose Mercury News report.
Marine algae called pseudo-nitzschia is the cause of this toxin, which kills brain cells and can result in brain damage for stranded sea lions based on research by a team at UC Santa Cruz. Much like Alzheimer’s, this condition harms the sea lions’ memory as well as its ability to navigate. Scientists have observed first-hand sea lions seeming confused or trembling on California beaches.
Basically, the sea lions have no sense of where to go and have difficulty finding food, which obviously threatens the creature’s survival.
It’s not uncommon to see harmful algal blooms, but this year’s bloom was particularly large and extended from as far north as Alaska all the way down to Santa Barbara, and it lasted through the summer. Most of them just last a few weeks in the spring.
In addition to sea lions, it’s caused other environmental problems, including forcing commercial Dungeness and rock cab fisheries to shut down throughout the state. It’s also affected razor clams, anchovies, and other food sea lions need to eat.
To make their findings, the researchers took some sea lions to a psychology lab to help them heal and also conduct some tests. They found that those with healthy brains could navigate a maze, while those that had been poisoned couldn’t adapt as easily to the maze. The animals also showed memory problems as well.
Scans of their brains showed a damaged hippocampus, which is the part of the brain responsible for memory and navigation.