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Whales in San Francisco Bay

Roughly 30 gray whales have been spotted in the Bay this season, many more than is typical. Sadly, there have also been at least 14 deaths this year, which is more than in all of 2024. 

We are investigating to help determine the cause of these deaths. By gaining insights into what is causing these tragedies, we can better understand how to help prevent them.

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California sea lion Pammysue

Algal Toxin Impairs Sea Lion Memory and Hippocampal Connectivity, With Implications for Strandings

Algal toxin impairs sea lion memory and hippocampal connectivity, with implications for strandings
  • Domoic acid

Abstract

Domoic acid (DA) is a naturally occurring neurotoxin known to harm marine animals. DA-producing algal blooms are increasing in size and frequency. Although chronic exposure is known to produce brain lesions, the influence of DA toxicosis on behavior in wild animals is unknown. We showed, in a large sample of wild sea lions, that spatial memory deficits are predicted by the extent of right dorsal hippocampal lesions related to natural exposure to DA and that exposure also disrupts hippocampal-thalamic brain networks. Because sea lions are dynamic foragers that rely on flexible navigation, impaired spatial memory may affect survival in the wild.


Cook, P.F., Reichmuth, C., Rouse, A.A., Libby, L.A., Dennison, S.E., Carmichael, O.T., Kruse-Elliott, K.T., Bloom, J., Singh, B., Fravel, V.A., Barbosa, L., Stuppino, J.J., Van Bonn, W.G., Gulland, F.M.D., Ranganath, C. 2015. Algal toxin impairs sea lion memory and hippocampal connectivity, with implications for strandings. Science. 350(6267): 1545-1547.

domoic acid

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