Periodic Reporting for period 1 - BlueShellfish (Solutions to prevent and mitigate the impacts of HABs in Aquaculture and Fisheries, in the context of global warming)
Période du rapport: 2023-01-01 au 2024-12-31
Harmful algal blooms (HABs) are characterized by the excessive growth of toxic phytoplankton. Driven by global warming and human activities, HABs are increasing in certain regions worldwide. These events have been linked to human illnesses mostly caused by the consumption of contaminated seafood. Additionally, HABs severely impact economic activities such as aquaculture and fisheries, impairing species growth, survival and contaminating fish stocks.
Although regulations on toxin levels in seafood and preventive measures—such as temporary shellfish harvest bans during HAB events— are contributing to reduce human poising, measures to reduce the impact of HABs in aquaculture and fisheries remain very limited.
This project aims to develop solutions for the aquaculture and fisheries sectors by improving HAB detection methods (early warning systems) and creating farming and depuration techniques to reduce toxin loads in shellfish. It also seeks to enhance the understanding of both regulated and emerging toxins, including their chemical and toxicological properties, global distribution, and persistence in seafood—particularly in under-studied species and non-traditional vectors.
To achieve these goals, an interdisciplinary consortium was built, bringing together scientists from different areas of specialization. Through collaborative R&I actions, the project will contribute to technological advancements in aquaculture and fisheries, to the sustainable growth of the sector and will deliver more tools for monitoring HABs.
Although regulations on toxin levels in seafood and preventive measures—such as temporary shellfish harvest bans during HAB events— are contributing to reduce human poising, measures to reduce the impact of HABs in aquaculture and fisheries remain very limited.
This project aims to develop solutions for the aquaculture and fisheries sectors by improving HAB detection methods (early warning systems) and creating farming and depuration techniques to reduce toxin loads in shellfish. It also seeks to enhance the understanding of both regulated and emerging toxins, including their chemical and toxicological properties, global distribution, and persistence in seafood—particularly in under-studied species and non-traditional vectors.
To achieve these goals, an interdisciplinary consortium was built, bringing together scientists from different areas of specialization. Through collaborative R&I actions, the project will contribute to technological advancements in aquaculture and fisheries, to the sustainable growth of the sector and will deliver more tools for monitoring HABs.
The work carried out by the consortium consist of multiple R&I activities, mainly dedicated to 1- the development of systems of alert of HABs, detection and quantification of biotoxins (with emphasis to ciguatoxins and tetrodotoxin); 2 - understanding the effects of climate change on the occurrence of toxic phytoplankton, its geographical distribution, chemical profile of toxins and contamination of seafood. Laboratory studies address in particular methods of immunosensing for the detection of biotoxins, analytical methods and clean-up methods to improve the analysis of biotoxins in complex matrices and in seafood. Other studies comprise field campaigns conducted in several countries (Portugal, Cuba, Mozambique, Brazil), aiming at disclosing new toxin vectors among seafood species consumed by Humans; laboratory experiments with toxic algae and shellfish aiming at understanding impacts of climate change in toxic algae and toxin profiles, and at understanding the metabolism of biotoxins in shellfish. The research has led to significant advancements in these areas of knowledge, as well as achieving other project objectives. Several dissemination and networking activities were organized in Portugal, Mozambique and Italy, contributing to knowledge sharing and transfer, capacity building of research teams and institutions, international and intersectoral cooperation, and exploitation of knowledge generated within the project.
Main results obtained during the first 2 years include the following: 1. Optimization of a colorimetric immunosensing protocol for the detection of Ciguatoxins (CTXs) in fish samples. The protocol includes a single step incubation followed by the signal measurement and enables the detection of CTXs in fish matrices within only 40 minutes at levels as low as 0.01 µg CTX1B equivalents/kg of fish, aligned with the safety guidance level proposed by the United States Food and Drug Administration (FDA). This approach significantly reduces both the complexity and time required for analysis compared to conventional methods, positioning this immunoassay as a highly promising tool for ciguatera poisoning risk assessment and management; 2. Cyclodextrin (CD) polymers were successful to clean-up and remove oyster matrix effects in the colorimetric CBA assay, which attains good Tetrodotoxin (TTX) recovery values, and provides 27-fold higher sensitivities, decreasing the LOQ down to 46 µg equiv. TTX/kg. This clean-up strategy with CD polymers combined with CBA could be implemented in the detection of TTXs in monitoring programs to ensure seafood safety; 3. Methods were optimized for the analysis of Cnidarian proteomes. These open new opportunities for the molecular studies in this ancient group of animals and the understanding of their metabolism, physiology and life cycle; 4. Acute exposure of bivalves to increased water temperature were investigated. Temperature demonstrated to affect significantly the metabolism of bivalves and the accumulation of the toxin okadaic acid, leading to the notion that marine heatwaves is an emerging stress factor, to be taken into account in the assessment of the impact of climate change in shellfish survival and contamination with marine toxins.