Mitigating harmful algal blooms with modified clay to safeguard marine aquaculture in a changing climate

Aquaculture is the fastest growing food sector globally. The FAO estimates its value at first sale to be ~ USD260 billion.

In Scotland the sector, dominated by the production of Atlantic Salmon, has a turnover of ~ £1.5 billion and supports ~ 12,000 jobs.

The continued sustainable development of the sector requires innovative measures to enhance production and to safeguard fish heath.

Whilst monitoring and modelling methods used to provide HAB early warning are improving, mitigation measures available to combat the occurrence of a bloom remain largely lacking.

Methods available to industry are primarily designed for "damage-limitation" such as the cessation of feeding to encourage fish to swim to deeper waters in the pen and hence reduce the oxygen demand in surface waters. This does not fully mitigate a HAB event, nor prevent significant fish mortalities.

Therefore, novel approaches to remove harmful phytoplankton blooms from fish cages are urgently required. the project has 4 aims.

These are to determine, at laboratory and aquarium tank scale, the impact of MC on: key harmful taxa (both diatoms and dinoflagellates) of concern to UK aquaculture; water chemistry (absorption and release of inorganic nutrients and metals);associated (benign) components of the microbial ecosystem (bacteria, other protists and zooplankton) ;the health and welfare of farmed fish (smolt Atlantic salmon).