Early detection of Harmful Algal Blooms (HABs) allows fish farmers to make timely key decisions in order to minimise the damage to aquaculture. To aid in this effort, a team led by Hatfield Consultants Ltd. (Hatfield), under the ESA-funded Chilean Aquaculture Project (CAP), has implemented an early warning service based on Earth Observation (EO) data, which delivers forecasts of potential HABs to aquaculture companies via a customised Internet portal.
HABs are a natural phenomenon that have increased in frequency over the last 30 years, causing millions of Euros worth of annual losses to the 360 fish farms found in the southern region of Chile. They deplete the concentration of oxygen in sea water, potentially killing larger caged fish such as salmon that cannot flee the affected area.
In the case of shellfish, such as mussels, toxins from the blooms accumulate in their body tissues and pose serious health risks for humans when consumed. For instance, in 2002 an HAB outbreak in Chile was responsible for 73 paralytic poisonings and two deaths. In 2004, more than 1500 cases of poisonings occurred resulting in an estimated 30 million Euro yearly loss. And in 2005, more than 10 000 cases were document, including one death.
Just like plants on land, algae employ green-pigmented chlorophyll for photosynthesis -- the process of turning sunlight into chemical energy. The chlorophyll collectively tints the colour of the surrounding water, providing a means of detecting these tiny organisms from space with dedicated 'ocean colour' sensors onboard satellites.'"/>