Low Trophic Aquaculture (LTA) focuses on the production of species that occupy lower levels of the food web. LTA consists of unfed aquaculture which includes filter feeders (e.g. mussels, oyster, and clams), detritivores (e.g. sea cucumbers), seaweed, but also herbivorous fish (e.g. carps). LTA aligns with sustainable aquaculture principles by reducing reliance on finite resources and minimizing environmental footprint.
The benefits of Low Trophic Aquaculture (LTA) are:
1. Reduced energy input: LTA focuses on species lower in the food chain, requiring less energy input compared to farming carnivorous species. This leads to more efficient resource utilization.
2. Improved aquatic ecosystems: LTA (specifically, filter feeders and seaweed farming) can absorb excess nitrogen, phosphorus and carbon thus mitigating eutrophication and climate change effects. Furthermore, LTA practices, can also improve water quality (e.g. mussels, oyster, and clams farming) through filtration and sea bottom quality (e.g. clams and sea cucumbers farming) through the movements of the farmed species in the sand.
3. Diversification: LTA expands the range of species that can be farmed sustainably, contributing to diversification within the EU aquaculture sector.
4. Potential for high-value product development: as highlighted by the ASTRAL project, LTA can provide raw materials for the production of food, feed, cosmetics, medicines, bioplastics, and other valuable products.
The challenges of Low Trophic Aquaculture (LTA) are:
1. Market demand and consumer acceptance: consumer demand for LTA products (e.g. seaweed) may be lower than for other species in certain regions1. Efforts are ongoing e.g. via the EU Aquaculture campaign and the EU Algae Initiative to increase awareness and acceptance of these products.
2. Regulatory frameworks: the regulatory frameworks governing LTA may be less developed than those for traditional aquaculture, potentially creating uncertainty for investors and operators (see FAQ on IMTA).
3. Dependency on environmental conditions: LTA, especially in open water can be vulnerable to changes in environmental conditions such as temperature, salinity, and nutrient availability. Extreme weather events can also pose a risk.
It's important to note that the benefits and challenges of LTA can vary depending on the species being farmed, the location of the farm, the production system and the specific management practices employed.
LTA and higher-trophic species production (e.g. production of carnivorous species) can be combined to potentially generate positive environmental benefits, such as nutrients uptake and carbon sequestration. The integration of LTA in higher-trophic species production is one of the principle on which Integrated Multitrophic Aquaculture (IMTA) is based on.
The “Strategic Guidelines for a more sustainable and competitive aquaculture sector for the period 2021 to 2030” emphasise the importance of diversification towards species with lower trophic levels.
The EU Algae Initiative aims to support the algae sector in the EU, including seaweed aquaculture by improving governance, developing business support mechanisms, raising awareness and acceptance for algae in the EU and improving algae knowledge, research and data and driving innovation.
The Aquaculture Advisory Committee (AAC) published in October 2024 a recommendation on this type of aquaculture, which can be found here: https://aac-europe.org/en/publication/aac-recommendation-on-promoting-l…
The European Union (EU) has funded several research projects related to LTA, with the objective of promoting the sustainability and competitiveness of aquaculture within the region. For instance, AquaVitae (https://aquavitaeproject.eu/ ), ASTRAL (https://www.astral-project.eu/), and ULTFARMS (https://maritime-spatial-planning.ec.europa.eu/projects/circular-low-tr…) are noteworthy, as they also contribute to the advancement of LTA and sustainable aquaculture practices.
ULTFARMS is a pioneering “Horizon Europe Ocean Mission” project with a vision to revolutionize LTA systems. Its mission is to optimize LTA production within challenging offshore conditions and low-salinity environments. By integrating innovative engineering, technical, ecological, and biological processes, ULTFARMS aims to establish a profitable, sustainable, and ecologically sound production chain of low-trophic level species (seaweed and molluscs) in offshore wind farms situated in the North Sea and Baltic Sea.