II.-Integrated Multi-Trophic Aquaculture (IMTA): land-based and sea-based, new species and systems

Case Studies

The Integrated Multi-trophic Aquaculture (IMTA) value chain joins the case studies focus on:

Various activities within one Case study are focusing on Land-based integrated multitrophic aquaculture (IMTA) and more specifically on new species processes and products to increase the production of low trophic species in the Atlantic. Various partners from academic and private institutions are participating in Land-based IMTA experiments that are taking place along the Atlantic Ocean, more specifically in France, Spain and South Africa. The preliminary results obtained during the first experimental stages focused on hatchery and nursery stages as well as grow out processes highlight interesting aspects to further develop these production methods.

In France, the company France Haliotis has performed experiments to improve techniques of abalone juvenile’s production under organic certification. Settlement plates, covered with the macroalgae Ulvella lens, were prepared using organic fertilisers to improve settlement and growth rates of the abalone H. tubercula sp. postlarvae. Three different organic fertilizers dosages were tested as well as plate preparation that consisted in scraping or washing them with high pressure hose. The quantity and frequency of fertilizer affected the larval settlement rate as it affected the protein content and at higher protein content of Ulvella lens higher settlement rates were observed.

Mechanical preparation of plates, scrapping, affected growth of post larvae as less diatoms, acting as postlarvae food source, were present on the plates. Finally, the IMTA set up in Land-based tanks nursery tanks, that included the addition of anemone Anemonia viridis, had no effect on abalone juveniles production and enabled the production of additional high value product within the system, that are of interest for gourmet restaurants.

In Spain, the ECOAQUA institute from the University of Las Palmas tested the effect of different feed on abalone H. tubercula sp. production in Land-based IMTA systems in flow through or recirculated systems, as well as the integration of sea cucumber within these systems. Abalone feeding experiments were performed to test the effect of sustainable vegetable and enriched protein sources provided by the IMTA produced macro algae.

The feeding regimes tested consisted in commercial feed provided by Marifeed, IMTA produced fresh macro algae and a mix of both. The results demonstrated a high survival with no significant differences between treatments in all systems. Animals fed exclusively commercial feed presented lower length and weight than the animals fed fresh macroalgae or a mix of the diets in both flow through and recirculating systems. Generally, the animals presented high growth when fed a mixture of fresh macroalga and commercial diet in both production systems tested for all parameters and they were no significant difference observed for the same treatment between the two production systems tested.

Sea cucumber Holothuria sanctori, were collected in the wild and stocked below abalone at two different densities of 3.75 and 2.5 specimens per square meter. The abalone were fed IMTA produced macroalgae or compound feed. When stocked at higher density sea cucumber presented lower growth rates and their growth was also affected by their feeding source as their growth was observed to be significantly higher when feeding on waste of abalone fed fresh macroalgae. These preliminary results are of interest to demonstrate the feasibility to integrate sea cucumber to abalone grow out processes and the possibility to produce additional species or product within the Land-based IMTA system tested.

In South Africa, experiments were performed by Rhodes University to optimise Land-based IMTA production of abalone in South African farms using farmed macroalgae produced onsite. The macroalgae Ulva sp. was harvested from two operating systems existing on the farm, an IMTA system and a non IMTA system. Ulva sp. was submitted to strict biosecure protocols before being included in a compound feed.

The feeding regimes tested included: (1) a control feed produced by Marifeed, (2) a similar feed that including 12% Ulva produced in non IMTA systems,  (3) another similar feed including 12% Ulva produced in IMTA systems, (4) the control feed supplemented with fresh non IMTA produced macroalgae and (5) the control feed supplemented with fresh IMTA produced macroalgae. The inclusion of Ulva sp. in compound feed, specially IMTA produced Ulva sp. increased abalone feed consumption and did not compromise H. midae growth. Preliminary results obtained are to be further investigated and will further strengthen the link between macroalgae and South African abalone industry.

Indicators of sustainability were collected from different production systems on a commercial, land-based abalone farm in South Africa that employs IMTA (abalone and Ulva sp.) and monoculture production systems with the same species. Similar sustainability indicators will also be collected from experimental-scale abalone, ulva and sea-cucumber IMTA systems.

Experiments performed in the different geographical areas indicate; the feasibility to develop innovative integrated processes in land-based integrated multitrophic aquaculture systems using new species that are not affecting the production of the associated species; and the fact that these processes can be implemented at different stages of the production cycle and in a diversity of production systems, operated under a similar integrated approach. The results also highlighted the interest to integrate IMTA produced macroalgae in compound feed in terms of animal health and nutrition and as alternatives to reduce production costs and develop sustainable production methods.


Photos by Univ. Las Palmas de Gran Canaria (Spain), France Haliotis (France), Rhodes University (South Africa).

  • Lead scientificpartner: RhodesUniversity.
  • Lead industrial partner: Wild Coast Abalone.

This case study will design, implement, test and evaluate the effects of a variety of sea-based IMTA systems in real-life, commercial scenarios in three different locations in Europe (Sweden, Faroe Islands and France) and South Africa.

Specific tasks will include:

  • Optimising macroalgae/mussel co-culture in South Africa
  • Determining the effects of using IMTA grown macroalgae as feed for abalone in terms of production, product quality and health benefits and product biosecurity.
  • Developing protocols for commercial scale sea-based co-culture system including abalone, sea-cucumber, queen scallop and macroalgae in France.
  • Investigating the influence of IMTA (including salmon-mussels-macroalgae) in a fjord ecosystem in the Faroe Islands.
  • Investigating the potential for co-culture of oysters and lobster in sea cages in Sweden.
  • Lead scientificpartner: Universidade Federal de Santa Catarina.
  • Lead industrial partner: Trevisan.

This case study will develop IMTA systems in Brazil to improve efficiency in production. Specific tasks will include:

  • Test different ratios and turbulence levels on floc characteristics in pond culture systems in Brazil.
  • Development of a pilot study in Brazil evaluating commercial shrimp production based on the new operational parameters and validate co-culture techniques for a selection of species and systems in regard to profitability optimisation, compatibility and societal acceptability.
  • Develop innovative technologies to optimise IMTA production in Brazil through the monitoring of their dynamics in the systems and along the trophic flow in terms of productivity, nutritional quality, and reduction of environmental impact, energy as well as nutrients and energy reuse.

Photos by Sylvain Huchette, France Haliotis, Cliff Jones, Rhodes University, and  Felipe Vieira, UFSC.