When consumers buy fish at the grocery store, they tend to think that wild caught fish is better than farmed fish. Your report tells us that aquaculture is actually the better alternative.
Adalberto Val: Fish captured in the wild cannot support the world population that we have today. If we don’t expand aquaculture we are going to have a mass extinction of fish in nature. But we can do it much better today than we used to. And the fish tastes better.
In 2022, for the first time the world consumed more farmed fish than captured fish. How can you make this production sustainable?
Klement Tockner: It is important to develop largely closed-loop systems. You can use the fish’s wastes to feed plants. In my former institute, the Leibniz Institute of Freshwater Ecology and Inland Fisheries, we developed what we call the “tomato fish,” where you have a closed system, and you also use the water for fertilizing tomatoes.
Is it true that the CO2 footprint of farmed fish is smaller than that of wild caught fish?
Val: To transport fish from the middle of the Amazon to the big cities, you waste a lot of energy. So raising fish in aquatic systems must happen close to the big cities.
Germany and Brazil are very different countries, not only geographically, but also in respect to fish consumption. Germany imports 98% of its fish, whereas people in the Amazon eat a lot of locally caught fish.
Val: Here in the Amazon, 90 percent of the protein that people consume comes from local fish. But the population in the Amazon is only about 10 percent of the country. The south of Brazil is very much like Germany. They don‘t eat a lot of fish.
How did you go about your joint project?
Tockner: It was a big learning exercise. In our workshop, we brought together primarily early career scientists from different disciplines from Brazil and Germany. We had some preparatory webinars, then we had the meeting in Berlin, and then the entire policy brief and all the recommendations were written by the young scientists. We are just the editors, our role was to empower and support them.
The development of new ways of sustainably producing fish is one thing, the other is to convince people to eat more fish.
Tockner: First of all, it has to be economically feasible. Artificial intelligence, for example, can help to increase the efficiency and effectiveness of aquaculture. The second is the perception of the public. Most people still think that wild caught fish tastes better than farmed fish and is more healthy and sustainable as well. We recommend introducing aquaculture as a protein source in college cafeterias and in primary schools to increase the acceptance.
What is going to happen after you publish your report?
Val: We will try to reach the politicians and decision-makers and the general public. Aquaculture would help to reduce the pressure on the rainforest immensely. In a big country like Brazil, the young scientists can take this information to local communities.
Tockner: Both academies have a very good reputation. The key goal of the Leopoldina is to give evidence-based policy advice. We have to make sure that the early-career scientists get rewarded for this work as well. Unfortunately, the scientific community doesn’t always recognize the writing of policy briefs like this.
The interview was conducted by Christoph Drösser