Harmful Algal Bloom Modelling and HABreports

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HAB Modelling

A mathematical model based early warning tool for advective harmful algal blooms in Scotland.

Harmful algal blooms in Scottish waters are often transported significant distances around the coast through the action of oceanographic currents. Hence, knowing the location of a bloom event allows mathematical model based forecast of its future development and location, offering the potential to provide early warning and risk assessment to other aquaculture businesses in the region

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A few algal species can produce toxins that can get into shellfish that are destined for the market. A weekly bulletin provided by SAMS to Seafood Shetland provides farmers with details on the water and prediction of risks of HABs.

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With the SAMS harmful algal bloom early warning web-portal (HABReports.org), we have implemented an operational model based forecast tool that uses SAMS’ operational forecasting modelling system WeStCOMS to predict the subsequent anticipated size and trajectory of HABs identified at or near aquaculture sites.

The model consists of coupled atmospheric (weather-research forecasts WRD 2km) and unstructured-grid finite volume community ocean modelling (FVCOM) components with up to 100 meters nearshore resolution.

Microscope counts of algal cells undertaken at aquaculture sites by finfish producers and through te Scottish regulatory shellfish safety monitoring programme ware used to initiate the model.  If cell counts exceed predefined threshold levels, virtual particles ‘seeded’ for advection into the flow fields, derived from an ensemble of suitable hydrodynamic forecasting models.

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HABReports Screenshot

This Screenshot is from HABreports.org and highlights modelled development identified in the Firth of Clyde on 28 September 2020. Coloured particles shows the modelled HAB spreading pattern prediction from our WeStCOMS-FCBOM model up to the 4 October 2020.

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HAB Reports

HABreports.org includes both map and time-series based visualization tools. A ‘traffic light’ index approach is used to highlight locations at elevated HAB/biotoxin risk.

High resolution mathematical modelling of cell advection, in combination with satellite remote sensing, provides early warning of HABs that are transported by oceanographic current from offshore waters to the coast.

Expert interpretation of HAB, biotoxin and environmental data, in light of recent and historical trends is used to provide, on a weekly basis, a forecast of the risk from HABs and their biotoxins to allow mitigation measures to be put in place by aquaculture businesses, should a HAB event by imminent.

The system was initially developed for the shellfish aquaculture sector but is now being expanded to include harmful phytoplankton of relevant to finfish aquaculture.

HABReports Screenshot

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Imaging Flow Cytobot

(Photo courtesy of HIE, Image credit Ben Mullay)

To enhance the HABReports alert system, SAMS and Shetland-UHI have undertaken the development of the UK’s first two Imaging Flow CytoBots. These are flow cytometer based instruments that allow the rapid identification and enumeration of phytoplankton including harmful species. These instruments have been deployed in two locations in Shetland waters on a trial basis to evaluate their potential to support decision making by aquaculture practitioners.

The IFCB based system allows for multiple phytoplankton samples to be analysed per hour with the data being streamed in real time on the web.