Emerita analoga (Stimpson) as an indicator species for paralytic shellfish poisoning toxicity along the California coast.

Paralytic shellfish poisoning toxins (PSPT) produced by certain harmful algal blooms (HABs) pose a serious threat to public health worldwide. Along the West coast of North America, Mytilus californianus (California sea mussel) has long been used as the primary indicator species for monitoring levels of PSPT in the environment. However, because the natural distribution of this species is limited to rocky shores, vast stretches of coastline bordered by sandy beach habitat are not regularly monitored for PSPT presence. This insufficient spatial coverage greatly reduces the ability to track and predict HAB development and movement along the open coast. Earlier studies on Emerita analoga (common mole or sand crab) demonstrated this species' potential to sequester the neurotoxin saxitoxin (STX) and its derivatives. The goals of this study were to (1) develop a practical and efficient PSPT extraction protocol for sand crabs, and (2) compare the utility and reliability of this species as an indicator of PSPT with that of mussels. Laboratory spike and recovery results showed that STX extraction efficiencies were very similar for both species. Field comparisons of natural accumulation and depuration rates of PSPT for the two species revealed that PSPT events detected using mussels were also identified with sand crabs.