Ostreopsis ovata monitoring programme

Ostreopsis ovata is a unicellular microscopic alga that usually lives in the warm waters of tropical seas. This microalga has developed in our seas as it has been transported in the bilge waters of ships and thanks to very favourable climate conditions.
Ostreopsis ovata blooms have been observed for years throughout the north-western Mediterranean, and in some cases they have been toxic to humans.

The toxic effects are usually limited to flu-like symptoms such as fever, cough, nausea, colds, conjunctivitis and respiratory disorders.
People who are affected by them have not necessarily been in direct contact with the water: as a matter of fact, it is sufficient to inhale wind borne droplets for symptoms to occur.

Over the past decade, much attention has been given to the development of species of the genus Ostreopsis (benthic dinoflagellates), many of which have proliferated in temperate seas.

Thanks to regular exchanges between working group members, work is continuing to increase scientific knowledge and to ensure health management of these toxic microalgae.


Ostreopsis ovata © Luisa Mangialajo

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RAMOGE has produced an animation video that gives an insight into this microalga

RAMOGE has produced an animation video that gives an insight into this microalga


Cryptogamie - Algologie (volume 33 n° 2 – Mai 2012)

Cryptogamie – Algologie (volume 33 n°2 – May 2012)

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Ostreopsis ovata database

Since 2010, RAMOGE has been collecting data on sightings of Ostreopsis ovata on the French, Italian, Monegasque and Spanish coasts.
These data can be accessed via the documents available for download below.