The microalgae Alexandrium minutum produces neurotoxins responsible for paralytic shellfish poisoning, which upon accumulation in shellfish represent a human health risk. This species recurrently forms toxic blooms in the Northern part of the French Brittany coast. At present, algae identification relies on tedious microscope observations mostly performed by skilled taxonomists in laboratories. Newly emerging fields of molecular taxonomy, nanoscale technology and biotechnology offer opportunities for the development of in-situ biosensors for the detection and the monitoring of toxic algae.