Flemish entrepreneur puts sustainable fish on the menu


A researcher-turned-entrepreneur is banking on a fish species he found in Australia to prove there’s money in sustainable fish farming

Tomato meets fish

Last month, Flemish environment minister Joke Schauvliege turned over the symbolic first shovels of dirt at the greenhouse cultivation zone Stokstorm, in the border area of Deinze and Kruishoutem in East Flanders, where a new fish farm will be built by next April.

The facility is unique in its focus on sustainability and intends to bring a new type of fish to the Flemish market through a highly eco-friendly breeding process, which involves collaboration with the tomato farm next door.

The Aqua4C project originated from the PhD research project of Stijn Van Hoestenberghe at the biosystems department of the University of Leuven (KU Leuven). Van Hoestenberghe founded and is heading the project, while KU Leuven continues to provide support, including financial assistance.

“After gaining experience in the commercial aquaculture sector, including work abroad, I decided to examine a way to farm fish in a more sustainable manner than is now the case,” Van Hoestenberghe explains.

One of the main goals of his PhD work was to find a fish species that could be bred using eco-friendly methods. He eventually found his winner at the other end of the world, in Australia. The fish is called the jade perch but is known as omegabaars (omega perch) in Dutch because it contains a lot of healthy Omega-3 fatty acids.

“One of the other important assets is that the fish are vegetarians,” Van Hoestenberghe continues. “Their diet is completely plant-based, so we don’t have to feed them fish oil or fish meal like with most other farmed species.”

The jade perch is, in addition, very resistant to diseases so antibiotics don’t have to be used in the filtering system, which is rare in fish breeding. “Our filtering system is entirely biological; we actually use bacteria to do the filtering, so antibiotics would make that technique impossible,” says Van Hoestenberghe.

A final significant advantage is that smaller water quantities than usual are necessary to cultivate the fish. The jade perch naturally acquired these characteristics since its normal habitat in Australia was in a desert area where rivers often dried up, so the fish had to live together in large numbers in small pools of water.

Teaming up

The collaboration with the adjacent tomato farm, Tomato Masters, further reduces the ecological impact of the fish-breeding enterprise. After the water has been purified, the residual and nutrient-enriched water from the fish farm will be transported to the greenhouses next door, where it will be used to grow tomatoes.

It was the culinary sector that pushed me to commercialise the research findings

- Stijn Van Hoestenberghe

The water is subsequently filtered and evaporates through the tomatoes. “Which means that we don’t produce waste water, and the farm can use less water and fertilisers,” Van Hoestenberghe says.

The tomato farm will in turn distribute its surplus electricity to the fish farm, where it will be used to heat the water, which will be especially helpful in the winter.

According to the founder, this collaboration technique is unique in the world. “There are projects in the US and Switzerland where the residual water of a fish farm is also used to grow vegetables, but the process always takes place in the same location,” explains Van Hoestenberghe. “We are the first to delink the processes and to carry it out commercially on a large scale.”

Aqua4C may have its roots in research, but today it is an unequivocally commercial enterprise. That makes the taste of the fish of crucial importance. According to Van Hoestenberghe, the jade perch tastes like sea perch when baked and like eel when smoked. “In the beginning, we had to adjust our filtering techniques and the choice of feed to improve the taste of the fish,” he says.

The Aqua4C founder says he had no difficulty convincing top chefs of the quality of the fish after those tweaks. “It was actually the culinary sector that pushed me to quickly exploit the research findings in a commercial business.”

Van Hoestenberghe hopes to get the farm off the ground by April of next year, with the first fish for sale in October. “We hope to attract the interest of specialist fish shops, caterers and restaurants,” he says. “Our enterprise will be too small for the demand of big supermarkets, at first.”

He expects to produce about 200 tonnes of fish a year, with one fish weighing between 600 and 800 grams, and he hopes to make an annual turnover of €1.5 million. The cost to launch the project was €3 million, which was financed through investments from 25 local partners, including KU Leuven, banks and business angels.

Photo by d’Artagnan/Chris Vlegels