By Margot Higgins Scientists have linked the deaths of sea lions off the coast of California to toxic algal blooms. Poisonous algae is responsible for the mysterious deaths in 1998 of more than 400 sea lions off the coast of California, according to a study published in the Jan. 6 issue of Nature . For the first time, scientists have identified all links in the food chain that tie toxic algal blooms to the deaths of marine mammals. In so doing, they determined the California sea lions were poisoned with domoic acid, a neuro-toxin generated by various marine algae that also affect birds, sea otters and even humans.
Toxic algae can bloom in many conditions and affect many levels of the marine food chain.
The California sea lions ate large quantities of anchovies and sardines that had fed on the algae. Since algal blooms occur quickly in areas that are difficult to monitor, tracking the toxin through the marine food chain has been difficult. Scientists have also been hard-pressed to determine the causes of death in marine animals since their carcasses often go undiscovered for days or weeks. Christopher Scholin, a molecular biologist with the Monterey Bay Aquarium Research Institute, researched the toxic algae phenomenon. While testing water samples for various algae in the spring of 1998, Scholin and his research team noticed increased amounts of the poisonous algae.