Scientists studying sea lions in California say there's an increase of animals affected by domoic acid, a toxin produced by specific types of algal blooms.
In high doses, domoic acid is fatal, but in lower doses, it can trigger miscarriages and cause gradual, irreversible decay of brain tissue, according to Frances Gulland of The Marine Mammal Center in Sausalito, Calif.
Algal blooms are believed to be caused by a combination of factors, including agricultural run-off, oceanographic properties and global warming.
In the last five years, more than 1,000 animals have died from domoic acid poisoning, says Gulland.
"Sea lions eat the same foods we do, but more of them -- foods like anchovies, squid, salmon, and mussels -- we may see the effects of domoic acid in them before we see it people," says Gulland. "Sea lions may be an early warning sign for humans."
The findings were presented at the American Association for the Advancement of Science in St. Louis.
Copyright 2006 by United Press International
Explore further: How were fossil tracks made by Early Triassic swimming reptiles so well preserved?