Mortalités de poissons d'élevage par phytoplancton toxique Camaret (Finistère), automne 1994

Brown water was observed in Camaret Cove, on 27 and 28 September 1994, because of the massive proliferation of a toxic phytoplankton alga. The densities reached by this alga were considerable: from 1.5 million cells per litre at a point far from the coast to 130 million cells per litre at the height of the efflorescence at the bottom of the bay, in the port's waters. The toxicity of this alga caused deaths in the farms of salmonids in cages set up at this site. The SEMII (IFREMERINRA research facility) experimental farm recorded 100% losses (15-20% on 27 September and the entire remaining stock during the night of 27-28 September), which is around 10 tonnes of fario trout and 0.5 tonne of Atlantic salmon. Aside from the economic loss, this represents a delay in the experiments in progress. A private farm, located slightly outside of the same site and that was able to move its cages outside of the most affected zone, was also affected but suffered a much less severe percentage of losses (15 tonnes of fario trout out of an annual production of 120 tonnes).