Sustainable management and efficient use of water resources are crucial in the fish production and processing sectors, particularly considering growing public concern for aquatic ecosystems. Tailoring water use and reuse to specific production or processing conditions is crucial, considering potential reusable sources, applications for reused water, treatment technologies, and operator capabilities to enhance both efficiency and sustainability in the seafood sector.
SEA EIGHT group ranked third among largest producers of sole in Europe in their farms located in Spain and Portugal. The hatchery at Safiestela S.A. in Póvoa de Varzim (Portugal) currently produces 2.5 million fry of Solea senegalensis annually, utilizing advanced techniques, as Shallow Raceways Systems (SRS), across its hatchery, weaning, nursery, and pre-ongrowing sections, all supported by Recirculating Aquaculture Systems (RAS). Currently, these systems usually generate 20-60 m3/hour in effluent rich in organic matter and nutrients such as nitrogen and phosphate, which could be used to supply water to different seaweed production systems. Aiming to enhance sustainable aquaculture, the INNOAQUA project, SEA EIGHT in collaboration with A4F (experienced in seaweed cultivation), will pilot a SMART-Integrated Multi-Trophic Aquaculture (IMTA) demonstration site located in Portugal, integrating seaweed cultivation with fish production by utilizing the nutrient-rich effluent to support macroalgae like Ulva and Gracilaria. This initiative addresses the technical knowledge gap traditionally seen in fish farms considering water treatment and promotes enhanced production efficiency.
DEMO#2 will be demonstrated that can allow the expansion of the seaweed system to potentially treat five times more water, corresponding to the entire water renovation needs in the nursery and pre-ongrowing stages, capable to produce several tons of fresh seaweed per month and removing more than 100kg of N annually. Furthermore, DEMO#2 will generate data on the microbiome and virome to better understand how these might be related between fish and algae and how they affect biomass and water quality.
Ultimately, this approach not only combats eutrophication but also maximizes space and resource efficiency, allowing for substantial biomass increases and product diversification in aquaculture. Land-based algae aquaculture, produced in this way, can contribute significantly towards the sustainability of European aquaculture while contributing also towards food safety and value creation.
