Introduction
Aquaculture systems across Europe are increasingly exposed to the impacts of climate change, with rising temperatures, heatwaves, floods, droughts, and extreme storm events already disrupting both freshwater and marine production. Among the most affected sectors is bivalve aquaculture, where the impact of more frequent and intense harmful algal blooms (HABs) is clear. These events pose significant risks to food safety, farm productivity, and coastal economies, particularly when toxinproducing microalgae are present. The EarlyTOX project was implemented to develop a rapid molecular detection approach based on quantitative real-time PCR (qPCR) and digital PCR (dPCR) technologies to detect and quantify toxin-producing microalgae in aquaculture environments, such as Gymnodinium catenatum, Gambierdiscus spp., and Ostreopsis spp..
Results and Discussion
To strengthen earlywarning capacity and improve risk management, molecular detection tools have become essential. qPCR, and dPCR enable rapid, sensitive, and speciesspecific identification of toxic microalgae in environmental samples. This is especially critical for taxa such as G. catenatum, where morphologically similar nontoxic species coexist within the same genus. By targeting genes directly involved in toxin biosynthesis, speciesspecific primers allow precise discrimination between toxic and nontoxic strains, reducing false positives and supporting current monitoring programs, that are time consuming, labour intensive, and highly dependent on taxonomix expertise, which can delay regulatory decisions. qPCR detection was already achieved for Gymnodinium catenatum, Gambierdiscus spp. and Ostreopsis spp., and dPCR will be optimized to enable highly sensitive and accurate identification and quantification of target species in more complex environmental samples. Results will be compared with monitoring data issued by The Portuguese Institute for the Ocean and Atmosphere (IPMA). This will validate the molecular tool under real-world conditions and evaluate its capacity to support early detection and risk assessment during HAB events. Optimization of detection protocols for other relevant species are ongoing (Dynophysis acuminata, Pseudo-nitzschia, Alexandrium, etc.)
Conclusions
The EarlyTOX project highlights the growing importance of molecular diagnostics in safeguarding aquaculture under climate stress. Integrating advanced detection methods with environmental monitoring provides a robust framework for mitigating HABrelated risks and enhancing the resilience of European aquaculture in a rapidly changing climate.
Acknowledgment
This work is financed by FCT - Foundation for Science and Technology, I.P., within the scope of the EarlyTOX, under ref.2024.17161.PEX, and Interface Mission cofinanced by PRR - Plano de Recupera����o e Resili��ncia by the European Union (operation code 01/C05-i02/2022.P148).