School of Sustainability

They raised the sturgeon in the river's own water first

On 18 September, on the bank of the Ina at Goleniów, several hundred people turned up to put fish into a river. Schoolchildren, anglers and pensioners tipped buckets and watched the water take them: fifteen larger juvenile Atlantic sturgeon, and several thousand smaller ones, each about fifteen centimetres long and a long way from the several-metre, 350-kilo animals their kind can become if left alone for enough decades. It was the first such release on the Polish side of the Oder Delta, following earlier ones in Germany.

The fish they were returning had been absent for a lifetime. Atlantic sturgeon once ran the Baltic tributaries in numbers, but the twentieth century took them apart piece by piece - overfishing first, then the straightening, deepening and embanking of rivers across the delta, pollution, the loss of spawning gravel, and weirs that stopped migrants reaching it. What disappeared was not a stock but a resident: an armoured, barbelled bottom-feeder whose foraging stirs the riverbed and whose migrations stitch fresh water to the Stettin Lagoon and the sea.

The Ina was chosen because years of unglamorous work had made it worth a sturgeon's time. The Rewilding Oder Delta team and local partners on both sides of the border have been pulling out migration barriers, restoring spawning grounds, rewetting wetlands and improving water quality along the catchment. A sturgeon is an unforgiving auditor of all this - it needs free-flowing, oxygen-rich water and clean gravel to breed - which is precisely why the partners want it back. A river that suits sturgeon suits salmon, eels and everything else that migrates.

The juveniles themselves were a cross-border production. The larvae came from Germany, where the Leibniz Institute of Freshwater Ecology and a Mecklenburg-Vorpommern research institute oversaw hatching, and the fish were grown out at the Polish Anglers Union's rearing centre in Goleniów. There they were fed only natural food, in tanks plumbed with water from the Wiśniówka, a small tributary of the Ina - so that by the time they slid into the river, its chemistry and smell were already familiar.

September's release is deliberately small. The plan is more than 20,000 young sturgeon in 2027, building towards as many as 100,000 juveniles a year, kept up long enough for the fish to come back on their own - which, for a species that matures slowly and can live for many decades, means the people at Goleniów will wait a long while to learn what their morning amounted to.

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