Marine biotoxins are poisons that are produced by certain kinds of microscopic algae that are naturally present in marine waters, normally in amounts too small to be harmful. Biotoxins accumulate in shellfish to levels that can cause illness or death in humans and other mammals that ingest them. Of critical concern is the neurotoxin, saxitoxin and related derivates. Ingestion of saxitoxin contaminated shellfish and finfish is responsible for the illness known as Paralytic shellfish poisoning (PSP). Saxitoxin is produced by the dinoflagellates Alexandrium, Pyrodinium, and Gymnodinium. Along the coast of Costa Rica, blooms of Pyrodinium and Gymnodinium have been reported since 1981. During 1999, blooms of these species caused 70 cases of PSP with 6 fatalities, leading to a shellfish closer for over 2 years because of consecutive blooms and a lack of resources to analysis these toxins in Costa Rica. Commercially important shellfish such as thorny oyster (Spondylus calcifer), Panama pearl oyster (Pinctada mazatlantic), mangrove cockle (Andara turculosa), and Guiana swamp mussel (Mytella guyanensis) are all known vectors for human intoxication.
The NOAA National Phytoplankton Monitoring Network is a community-based volunteer science approach to monitor harmful algal blooms and their associated toxins. Founded in 2001, the network has trained over 600 volunteers across 36 U.S. states and 4 countries including Costa Rica. Since 2022, the network has partnered with Innoceana, a global marine conservation organization that works to preserve the ocean for future generations by empowering coastal communities through access to education and innovative tools, to monitor potential harmful algae along Isla Violin. This project will expand the initial sampling conducted by increasing the number of sites coupled with toxin detection and involve local schools and community groups to monitor the entire coast of Costa Rica.