Safe and Sustainable Shellfish: Introducing local testing and management solutions

Lead Research Organisation: The Robert Gordon University
Department Name: School of Pharmacy and Life Sciences

Abstract

Phytoplankton (algae) are essential in marine ecosystems determining fisheries productivity however around 2% of marine phytoplankton species produce biotoxins that can accumulate in harvested shellfish, posing a threat to human health. Harvesting of shellfish, including mussels, scallops and oysters, is an important part of the UK aquaculture industry worth around £40 million per annum and supporting over 3,000 rural jobs. The harvested shellfish are an important source of protein with markets at home and abroad. There is significant potential to expand this industry, however, harvesting can be halted, particularly in the summer months, due to the presence of harmful algae in the sea which can accumulate in the filter feeding shellfish. Monitoring of water and shellfish for the presence of biotoxins helps determine if it is safe to harvest, and where closure occurs it has been reported to cost a single farm in excess of £160,000 per annum. This consortium brings together three new technologies and world class expertise to provide an early warning, near instant biotoxin detection and a system to protect harvesting sites during harmful algal events. This is a unique opportunity to exploit research three separate developments initially funded by RCUK, allowing their deployment to be expertly utilised through the direct collaboration of shellfish farmer, government regulators and trade associations. The first of the exciting new technologies is the e-mice, so called because although in a single small (6x12x6 cm) electronic instrument we aim to detect all groups of regulated biotoxins with the potential to include other biotoxins which may be regulated in the future. Not so long ago consumer safety was ensured by the use of a mouse bioassay, this has now been replaced by sophisticated analytical detection systems. Currently it takes around 1-week and multiple methods to obtain results however, the e-mice will be developed to provide a format that can be used at a shelish harvesting site and give instant results supporting rapid management decisions regarding harvesting or protection of the shellfish grounds. Detecting toxicity once it has already accumulated can often limit the management options therefore this collaboration includes the satellite-based early warning system called ShellEye which will help predict harmful algae events and particularly their location with respects to shellfish harvesting areas. Data obtained from satellite imagery will be correlated with phytoplankton monitoring and biotoxin detection in phytoplankton samples. Early warning will then be used to make decisions on when to use the third of the innovative technologies which is the photocatalytic curtain. Also, pioneered under a different RCUK research project, the TiO2-based catalytic pods have specifically been designed to facilitate the treatment of biotoxins and algae in reservoirs in developing countries. The work planned here will explore their optimum configuration for use in a marine environment in a way that will protect harvesting sites, hence the concept of the reactive curtain. The benefits of using this technology is that no chemicals are discharged into the water, the catalyst when illuminated produces high energy, short life hydroxyl radicals which destroy organic molecules and can be active against microorganisms. The project will be underpinned by developing the capacity to produce all the required, phytoplankton, biotoxins and reference material to fully validate the e-mice during development and field use while also supporting photocatalytic optimisation. The culmination of the project will be the development of an integrated management strategy where all partners from industry, the regulators and academics will contribute to a practical close to real-time monitoring and protection of shellfish harvesting areas. This will in turn limit harvesting loses and ensure confidence to support expansion of this aquaculture industry.

Technical Summary

Shellfish are monitored for biotoxins to protect the consumer, initially based on mice bioassays, advanced analytical methods are now used. These methods depending on costly LC/MS/MS and a high degree of expertise. The vision of this research consortium is to roll out a simple testing device (e-mice) which is based on a unique lab-on-a-chip array. This will use biotoxin specific antibodies to regulated (OA, STX, AZA, DA) and emerging toxins (TTX, SPX, MC, CYN) and a nanoplotter for their immobilization onto the planar waveguide chip. The the small instrument will interface with a phone App for portability. We have used the plural term e-mice as the single instrument will instantly provide detect multiple regulated biotoxins below regulatory limits. The development of the e-mice will be supported by purified biotoxins, preparation of certified reference material and LC/MS/MS validation. Prediction of Harmful algal blooms (HABs) will integrate the work of ShellEye which employs satellite data by detecting pigmentation of algal blooms. This will be correlated with field sampling and near real-time biotoxin detection in phytoplankton samples using the e-mice. To fully mitigate against the significant financial loses which can be incurred during HAB incidents, the consortium will develop and evaluate the use of a protective photocatalytic curtain. This will exploit a new technology being pioneered in freshwater for cyanobacteria and their toxins. This simple but elegant approach uses the powerful photocatalyst, TiO2, on recycled foamed glass beads in glass-mess pods. Illuminating the TiO2 with near UV (360 nm) is now possible in-situ using low cost, low energy LEDs. This treatment will be effective against both phytoplankton and dissolved biotoxins. The culmination of the project will be a well-informed management strategy which will limit the impact of HAB incidents through near-real-time monitoring, protection of harvesting grounds and informed management decisions.

Planned Impact

The world's population is predicted to increase to almost 10 billion by 2050 and it is essential to provide safe and sustainable farmed seafood which has led the UK Government to establish the Collaborative Centre for Sustainable Aquaculture Futures in October 2017. Shellfish represent an important industry in the UK, employing >3000 workers and producing a revenue in excess of £40 million per annum. Furthermore, shellfish are a very important source of protein globally, with consumption predicted to rise both in countries where it is a long established component of the diet, and in those where it is an emergent market. However, the industry is vulnerable to the occurrence of harmful algal blooms (HABs), which occur when toxic phytoplankton are consumed by commercial shellfish, resulting in significant losses (£25 k/week for a single farm) when harvesting is closed down, or ill in health in countries where monitoring systems are not robust. In addition, the influence of extreme weather events and global transportation, has led to the occurrence of biotoxins previously not detected in UK waters and/or shellfish posing a future threat to the industry.

This consortium is bringing together the success and expertise of 3 technological advances namely a rapid biotoxin detection system, e-mice; for simple, validated, quantitative diagnosis of toxins (regulated and emerging) in the field. Secondly, advances in satellite remote sensing for early warning and finally using the well proven rapid destruction capabilities of TiO2 photocatalysis for the destruction of cells and biotoxins. Data from trials with e-mice will be correlated with satellite data from the ShellEye II project to determine potential for end-user predictive management. Safe in-situ remediation will be deployed for the first time to limit cells and toxins, thereby preventing closure of shellfish sites. This combination of early warning, rapid diagnosis and remediation will empower growers to make rapid desions resulting in economic production of safe shellfish.

The impact of this project will firstly be the positive benefits to the shellfish industry in the UK, although once proven in this country it is anticipated that there will be global market for the e-mice. It will readily be adopted across Europe, North America & Australia where the potential markets both for the device and the ongoing consumables will be significant. Since the aim of the final configuration is to interface with a smart phone the barriers to adoption in all shellfish harvesting areas of the world will be minimal as much of the operation and results can be designed for visual reporting which is not limited to a single language. Furthermore, the development of the e-mice can potentially be extended to detect pathogens (e.g. norovirus, E. coli) and other harmful chemicals extending this single platform across a range of applications. The impact of this device is not just limited to the financial market but primarily to health protection in that it can facilitate easy local testing protecting consumers from potentially harmful levels of toxins.

The provision of validated early warning of HABs will have an impact directly on shellfish farmers allowing remedial action before critical levels of contamination have occurred. Combining this with the truly innovative design of in-water photocatalytic treatment to respond to incidents and allow harvesting to continue even when threatened by HABs. The design of the photocatalytic curtain is based on over 20 years' study into the destruction of toxins and microbes, however, only recently has it been possible, with developments in other fields (material science & low cost LEDs), to deploy this technology at large scale in water. Success of this technology has potential to empower shellfish grower to protect and develop their industry and it is envisaged that once this has been demonstrated this treatment method can be applied in other settings.

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