Improving the prediction of harmful algal blooms in the Scottish Shetland Islands

The Shellfish Industry is highly important for the Shetland Islands. In 2014 around 77% of Scottish mussels were grown in Shetland. This commerce is worth approximately £6.8 million per year and supports 12-13% of jobs on the... [ view full abstract ]

The Shellfish Industry is highly important for the Shetland Islands. In 2014 around 77% of Scottish mussels were grown in Shetland. This commerce is worth approximately £6.8 million per year and supports 12-13% of jobs on the islands, either directly or indirectly. The complex coastline around Shetland, particularly the west coast, provides many sheltered voes perfect for shellfish aquaculture. This complexity, however, means that early warning or predictive modelling of phytoplankton movement and their associated toxins is difficult. Large Dinophysis spp. blooms during 2006 and 2013 badly affected the shellfish industry in Shetland. Analysis has revealed that advection governed by changes in prevalent wind patterns, rather than in situ growth, was the main reason the abundance of Dinophysis spp. around shellfish aquaculture sites increased so dramatically. Using the North Atlantic Oscillation (NAO) climate index as a tool to predict wind direction has shown some promising results, but changes in wind patterns do not always precede harmful algal blooms (HABs). To further investigate Shetland HAB historical data of phytoplankton abundance and toxicity from official control monitoring have been analysed in relation to climate indices. Further field work in 2017 will also evaluate the role of mixing fronts around Shetland as a source of HAB species for advection to coastal aquaculture sites. These activities complement the ongoing effort to improve the predictability of HABs in the Shetland Isles and hence improve the safety of molluscan shellfish.