Home > Explore Data & Reports > Blurred lines: Multiple freshwater and marine algal toxins at the land-sea interface of San Francisco Bay, California


Peacock, M.B., C.M. Gibble, D.B. Senn, J.E. Cloern, and R.M. Kudela. 2018. Blurred lines: Multiple freshwater and marine algal toxins at the land-sea interface of San Francisco Bay, California. Harmful Algae, 73:138-147. doi:10.1016/j.hal.2018.02.005

Data/Report Type:

Sponsored Research


San Francisco Bay (SFB) is a eutrophic estuary that harbors both freshwater and marine toxigenic organisms that are responsible for harmful algal blooms. While there are few commercial fishery harvests within SFB, recreational and subsistence harvesting for shellfish is common. Coastal shellfish are monitored for domoic acid and paralytic shellfish toxins (PSTs), but within SFB there is no routine monitoring for either toxin. Dinophysis shellfish toxins (DSTs) and freshwater microcystins are also present within SFB, but not routinely monitored. Acute exposure to any of these toxin groups has severe consequences for marine organisms and humans, but chronic exposure to sub-lethal doses, or synergistic effects from multiple toxins, are poorly understood and rarely addressed. This study documents the occurrence of domoic acid and microcystins in SFB from 2011 to 2016, and identifies domoic acid, microcystins, DSTs, and PSTs in marine mussels within SFB in 2012, 2014, and 2015. At least one toxin was detected in 99% of mussel samples, and all four toxin suites were identified in 37% of mussels. The presence of these toxins in marine mussels indicates that wildlife and humans who consume them are exposed to toxins at both sub-lethal and acute levels. As such, there are potential deleterious impacts for marine organisms and humans and these effects are unlikely to be documented. These results demonstrate the need for regular monitoring of marine and freshwater toxins in SFB, and suggest that co-occurrence of multiple toxins is a potential threat in other ecosystems where freshwater and seawater mix.

Note to readers with disabilities: Some scientific publications linked from this website may not conform to Section 508 accessibility standards due to the complexity of the information being presented. If you need assistance accessing this electronic content, please contact the lead/corresponding author, Primary Contact, or nccos.webcontent@noaa.gov.

Explore Similar Data/Reports

NCCOS delivers ecosystem science solutions for stewardship of the nation’s ocean and coastal resources, in direct support of NOS priorities, offices, and customers, and to sustain thriving coastal communities and economies.

National Centers for Coastal Ocean Science
1305 East West Highway, Rm 8110
Silver Spring, MD 20910
Phone: (240) 533-0300 / Fax: (301) 713-4353
Email: nccos.webcontent@noaa.gov

    Sign Up for Our Quarterly Newsletter