Document Type

Capstone Project

Degree Name

Bachelor of Science (B.S.)


Science & Environmental Policy


looms of domoic acid (DA) synthesizing diatoms (Pseudo-nitzschia spp.) have been associated with the death and injury of hundreds of marine shorebirds and mammals, exposed humans to potentially serious health risks, and threatened to significantly impact coastal fisheries and economies dependent on marine resources. While indicator organisms are widely utilized to monitor for marine biotoxins like paralytic shellfish poisoning (PSP) toxins, a reliable intertidal indicator species to monitor DA remains to be identified. Here we evaluate and confirm the utility of the common sand crab (Emerita analoga) as an indicator for DA in comparison with mussels (Mytilus californianus), a general sentinel indicator. Mussels and sand crabs, collected from natural populations in Santa Cruz, California (Apr. 1999-Feb. 2000), were tested for DA using the HPLC-UV method. Toxin loads in sand crabs ranged from 0.07 to 10.4 ug DA g⁻¹ and coincided with abundance of DA producing Pseudo-nitzschia species nearshore. The toxin was not detected in any of the mussel samples collected during the study period. The rise and fall of DA in sand crabs in synchrony with Pseudo-nitzschia abundance, combined with this common intertidal species' accessibility and ease of DA extraction, recommend sand crabs as a reliable, cost-effective monitoring tool for DA in the coastal environment.


Capstone Project (B.S.) Earth Systems Science & Policy Institute

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