A team of the Helmholtz Centre for Polar and Marine Research (AWI) researchers, together with industrial partners from Oceanloop and Sander, has successfully farmed the Queensland giant grouper (Epinephelus lanceolatus) in RAS for the first time in Europe collaborating with Ecomarine, an Australian pioneer in farming that species.
Several batches of 3g fingerlings have been successfully shipped from The Company One, an Australian hatchery that reproduces this species year-round, and acclimated at the AWI's Centre for Aquaculture Research. In addition to demonstrating the feasibility of transporting fingerlings over long distances, other research questions were addressed. The main focus has been on feed development and stress response at different stocking densities, as this species generally shows a high level of acceptance. Various stocking densities have been tested, ranging from 60 to 200 kg per m³. The results show no significant deterioration in growth or feed conversion. Blood stress parameters such as cortisol, glucose or lactate also showed no significant differences indicating the potential to farm this species at much higher densities than other marine species.
The feed development started mainly by testing available commercial feeds with different protein/fat ratios. The best results were achieved with diets above 50% protein and below 15% fat level. Improvements have been seen in growth, feed conversion, slaughter and filet yield. The results have been used by Oceanloop to manufacture a grouper feed, which has been successfully used for a farming trial at their R&D system in Kiel. The performance was out-competing the assumptions of the predictive modeling. The fish can grow up to 3kg in the first year from fingerling size at an economic feed conversion of 1.0. The survival rate in the trial over almost one year was 99%. Stocking densities varied between 80-120 kg per m³.
Proof-of-concept sales of grouper started via Oceanloop’s sister company Honest Catch with an introduction of the fish at the August menu of the famous **Michelin restaurant Ikarus of Red Bullin Salzburg, Austria. In November 2024, sales of a small initial volume of fish to private customers started with the launch of the nose-to-tail brand “Good Grouper” through the Honest Catch e-commerce platform. The first sales confirm the high potential of grouper in Europe as the taste and the high meat quality meet customer expectations.
Mirko Bögner, project coordinator at the AWI, emphasizes the importance of transferring research into commercial applications. "We're proud that the Opti-RAS project has provided valuable insights into the commercialization of grouper farming in European RAS and that this promising species has already found its way to seafood lovers.”
"We see great potential in farming this species. Growth, feed conversion and survival are excellent and, together with the stocking densities that can be achieved, this species can be a very sustainable marine fish species to be farmed,” said Bert Wecker, CTO of Oceanloop.
According to the consortium members, grouper is an important piece of the puzzle for the development of RAS aquaculture, as it requires suitable species with attractive price points. This species can be a potentially high-performing fish for RAS farming.
The project is supported by funds from the Federal Ministry of Research and Education (BMBF) within the Innovation Space Bioeconomy on Marine Sites (BaMS).
