The zander that this Serbian raises uniquely in Europe, and probably in the world, graces the luxurious tables of Switzerland and Japan, even before the elite at the prestigious forum in Davos. He spawns the fish naturally, without hormones, and uses no antibiotics in the farming process, thereby creating a premium product of exceptional quality—and price.
Lis is a small town about thirty kilometres from Bern. Nestled in a serene Swiss valley, the yards even have palm and olive trees. On the outskirts, under the roof of an apparently ordinary industrial hall, a unique and vitally important story unfolds. Here, as a pilot project, Georg O. Heriger founded the company Swifish AG in 2015, and in 2019, Milan Spasić joined the small team. With a degree from the Faculty of Biology in Belgrade and a thesis in fisheries from the Faculty of Agriculture, as well as professional training in Norway, this man from Leskovac was an excellent addition. In the land of cheese and chocolate, he develops new techniques for farming zander—a fish that has been commercially farmed for only about twenty years and whose life cycle, especially spawning, remains largely unknown. It is precisely the spawning that sets Swifish AG apart from the rest of the world.
“We spawn zander very similarly to the natural way, spontaneously on nests, because the welfare of the fish is important to us. We do not mistreat the fish like other fish farms, where they give them hormones and then sew up their genital openings to open them when they deem the right time and place for laying eggs,” Spasić points out.
Here, the fish feel the spawning time themselves, performing a courtship dance. But these parent fish are specially selected and cared for. As seen in the office, everything is on a large screen, all programmed and controlled with a click - food, water, temperature, light... We enter the facility. The same screen inside, but also darkness. A red lamp illuminates a tank full of small fish.
“They are mainly nocturnal animals, feeding in the morning and evening, so we mostly use red light, which they do not see and which does not bother them,” Milan says while showing us the fry - fish that have recently hatched.
The fry are the final product of this hatchery. After three months, they are moved 200 km away to a larger Swifish AG facility in the canton of Valais. There, they grow into fish weighing up to two kilos in the highest quality water from Alpine springs. There, they are filleted and sent to the market and onto plates.
Here in Lis, the main focus is on the parent fish, which must be the best and produce the best fry.
“My specific task is constantly monitoring the condition and health of the parent fish. This means they must not receive hormones or antibiotics if they need treatment. With appropriate sampling of oocytes (egg cells) from females, we fine-tune the water parameters so that the parent fish feel natural signals and spawn just like in nature,” Milan explains while showing us a microscope under which he examines eggs taken from the fish's abdomen using a catheter and syringe, predicting the outcome.
This outcome is achieved by simulating nature and all four seasons.
“We have four groups of parent fish, each with about thirty fish. They have different origins - Germany, the Netherlands, Hungary, and Denmark. To know which fish is which, and their offspring, all parent fish have a chip. This avoids inbreeding and ensures genetically quality fry. Each group of fish also carries a colour tag on their backs, so I can distinguish them on camera.”
Each group is in a different season simultaneously. One is always in spring when spawning is due. Thus, they produce quality zander fry throughout the year, while each parent fish undergoes a full cycle from spawning to spawning, just like in nature.
Here is a tank full of parent fish. They are between four to seven years old, the ideal age for breeding. Some are swollen with bellies full of eggs.
“The zander picks up signals from outside - the length of the day, light intensity, water temperature... and the trigger for spawning is spring. In this tank, it is spring, we have set the water temperature to 12 degrees and a long day. Therefore, the fish receive stimuli in the brain and send sex hormones indicating it is time to spawn,” explains the biologist while showing us the winter tank with six-degree water.
In nature, stimuli drive males to shallow areas of the lake to find a good spot for a nest.
“With their tails, they make nests, fight for territory, and a week to three weeks later, the females come and choose the best one. Then the courtship dance begins at the nest. It is the same here. The nests are artificial, made of bent plastic brushes, but they are nests. I will soon set them for these parent fish. After spending some time in this dance, they are ready—the female lays eggs, followed by the male's sperm (milt). Incubation begins. She leaves, and he stays at the nest, guarding it for five to seven days until the larvae hatch.”
About 450,000 larvae are produced in one cycle. Multiply that by four—almost two million in a year. However, due to natural mortality, about 15-20 percent of the fish remain, which is about 45,000 to 60,000 in one cycle. After three months here and another 10-14 months in Valais, they are ready for customers. A kilogram of fillet costs between 60 and 80 francs in Swiss markets. Expensive even by Swiss standards.
“The final product is of high quality thanks to genetically superior fry, modern technology, and exceptionally clean water from the Alps, allowing us to market it to the demanding Swiss market and the world-renowned Davos, as well as Japan,” Milan points out.
And the taste is divine. Without exaggeration...
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