The South African west and south coasts suffer from frequent occurrence of Harmful Algal Blooms (HABs). These blooms can have considerable negative impacts on commercial marine concerns such as rock lobster and aquaculture operations, in addition to local marine ecosystems and communities. HAB impacts come about either from the toxicity of some bloom species, or collapse of high biomass blooms through nutrient exhaustion, leading in extreme cases to hypoxia and dramatic mortalities of marine organisms, of which crayfish strandings are the most well known.
The HAB Decision Support Tool provides a capability for monitoring and assessing risk of HAB events, based on quantified understanding of bloom dynamics (Pitcher & Nelson, 2006), hypoxic impacts (Pitcher et al 2014), and earth observation monitoring capabilities (Bernard et al 2006). The example shown below focuses on bloom and hypoxia risk warnings for the St Helena Bay region - there will be broader HAB monitoring capabilities available for the entire national coastal area. Maps of sea surface temperature, ocean winds and ocean colour-derived phytoplankton biomass proxies are used to provide information on the presence and movement of blooms, and extracted time series of these data provide a "virtual buoy" capability giving a multi-parameter risk index.
Earth observation data used here are: