FRANK KANE AND PAULINE O’DONOHOE: Integrated Multi-Trophic Aquaculture: a role in

Integrated Multi-Trophic Aquaculture: a role in delivering the European Green Deal

Frank Kane and Pauline O’Donohoe, Marine Institute

What is the future of Irish Aquaculture?

In general, there is a growing demand for more circularity in processes and more sustainable practices across all industries.

Economic decoupling is a vital component of the European Green Deal, aiming to achieve economic growth while preserving a healthy environment. The aquaculture industry will be included in this shift to minimise or eliminate impacts, reduce waste, and increase circularity.

The European Green Deal provides an opportunity for the Irish aquaculture sector to position itself as part of sustainable food production. Again, Ireland led the way with organic production and can again show how integrated multi-trophic aquaculture (IMTA).

IMTA offers a potential avenue to enable aquaculture’s transition to a circular model while increasing productivity and supplying quality, sustainable seafood. The concept is a simple idea, where multiple aquaculture species are farmed on the same site or close to each other in an integrated and complementary way.

The key element is the interactions on the farm or the bay between the different trophic levels (different levels in the food chain). The wastes produced by the fed species (e.g. fish) is utilised as a feed, fertiliser and energy source for the lower trophic filter-feeding and extractive species (e.g. shellfish and seaweeds).

This has the benefit of lowering the environmental load in the water and allowing a more circular and sustainable approach to farming. The concept of nutrient recycling reflects practices in agriculture, where manure is spread to fertilise fields and facilitate grass growth.

The classic view of an IMTA set-up is based on a fed element (fin-fish) coupled with extractive species (shellfish and seaweed). The waste from the fed fish is in the form of particulate waste (faecal matter, uneaten food) and dissolved matter (metabolic waste (nitrogen)), acting as a nutrient source for other species.

The particulate waste serves as a food source for filter feeders and deposit feeders, while the dissolved waste serves as nutrients for seaweed production. This arrangement is doubly beneficial, as it increases growth in the extractive species and reduces the amount of waste material entering the environment, thus minimising any potential impact.

The concept can be considered holistically; the nutrient balance within a biological area or bay facilitates the planning of IMTA systems to ‘balance’ aquaculture in a broader ecosystem. For example, freshwater IMTA systems utilise hydroponics to grow valuable plant species in nutrient-rich wastewater and reducing potential discharge impacts.

Lehanagh Pool Research Site, Marine Institute

Seaweed on longline. Photo by Tom McDermott

Scallops in net. Photo by Frank Kane

The European Union recognises the potential of IMTA and has funded several research projects in this area. The Marine Institute is involved in a number of these projects supporting the Irish aquaculture sector.

The IMPAQT project (Intelligent management system for integrated multitrophic aquaculture) is currently carrying out IMTA research at the aquaculture research site in Lehanagh Pool, Co Galway, together with five pilot sites, both freshwater and marine, across Europe, Turkey and China.

The project aims to validate the concept of IMTA by designing and implementing cost-efficient technologies in monitoring and managing IMTA and demonstrating optimal sustainable development based on ecosystem services and circular economy principles.

The project is developing intelligent technologies to enable the smart management of IMTA systems, progressing models to understand better and plan IMTA set-ups, and utilising pilot systems to demonstrate reduced environmental impacts, sustainability of the concept, and the socioeconomic benefits accrued.

The ASTRAL project (All Atlantic Ocean Sustainable, Profitable and Resilient Aquaculture) develops new, sustainable, profitable and resilient value chains for IMTA production. It will assess the added value of the new species and novel species combinations throughout the production cycles, evaluate the potential for productivity, sustainability, profitability, and consumer trust. It will design and validate innovative technology for monitoring the production and environment.

The marine research site at Lehanagh Pool will serve as an ‘IMTA Lab’ within this project and IMTA sites in Brazil, South Africa, Argentina, and Scotland.

The INEVAL project (Increasing Echinoderm Value Chains), with Galway-Mayo Institute of Technology, will advance high-quality bio-economic products and services from echinoderm biomass by exploring the potential of sea-urchins, sea stars, and sea cucumbers as site remediation or marketable products.

IMTA allows greater biomass production from a site while reducing the environmental impacts, closing the circularity, optimising the use of space, and providing diversity in product and economic streams. The bioremediation value of IMTA is one of the most relevant and valuable contributions it can make, improving sustainability and the environmental credentials of the industry, allowing the eco-intensification of aquaculture.

It can be seen as an important tool to facilitate the sustainable growth of aquaculture, marine and freshwater, and promote its future development. IMTA offers the potential to enable the sector’s growth while preserving a healthy environment and provides a new opportunity for Irish aquaculture.

The IMPAQT Project (Intelligent Management system for integrated multitrophic aquaculture) is currently carrying out IMTA research at the aquaculture research site in Lehanagh Pool, Co Galway, together with five pilot sites, both freshwater and marine, across Europe, Turkey and China.

The project aims to validate the concept of IMTA by designing and implementing cost-efficient technologies in monitoring and managing IMTA and demonstrating optimal sustainable development based on ecosystem services and circular economy principles.