Back from the brink: How scientists are saving the Baltic sturgeon

Release of Baltic sturgeon into the Oder river for a telemetry study.
© LFA

The Baltic sturgeon has been vanishing at a startling rate in recent decades, at one point becoming essentially extinct. German scientists are leading efforts to reintroduce Baltic sturgeon to their native waterways and to protect existing populations through the EU-funded ‘Stör’ project.

Living fossils

Sturgeon are living fossils, having existed in the seas and rivers of the northern hemisphere for over 200 million years. Despite being one of the most species-diverse groups of living fossils, sturgeon are also one of the most endangered, with dramatic declines in recent decades due to river damming, overfishing and pollution. This is particularly true of the Baltic sturgeon, which was declared regionally extinct in 2013. The sturgeon is also protected under the EU Habitats Directive and was classified as a priority species group by the EU Marine Action Plan, which called on EU countries to take action to reduce the impact of fishing on this sensitive species.

The Stör project

The Institute of Fisheries at the Mecklenburg-Vorpommern Research Centre for Agriculture and Fisheries (LFA) in Germany is leading efforts to reintroduce Baltic sturgeon to their native waterways and to protect existing populations through the EMFF/EMFAF-funded -funded Stör project.

This multinational project is part of the HELCOM Action Plan for the protection and recovery of the Baltic sturgeon, and aims to recover extinct populations through spawning management, re-stocking, protection of wild populations and public relations activities undertaken in close cooperation with partners throughout the EU. The researchers at LFA MV are active members of the HELCOM EG Stur, an expert group for the restoration of sturgeon populations in the Baltic Sea region.

Research, re-stock, recover

At the heart of the project is LFA’s aquaculture facility in Born, situated on a brackish waterway of the Darß peninsula in the sturgeon’s native habitat.

In 2010, the Born facility oversaw Europe’s first successful reproduction of Baltic sturgeon. Since then, LFA has been the sole continuous producer of Baltic sturgeon for yearly re-stocking, both in Germany and other Baltic states. But producing and rearing sturgeon is only one step on the journey to recovery: effective re-stocking and monitoring of populations is also crucial for long-term success.

Sturgeon have a long-lasting and far-reaching lifecycle spanning several years and multiple geographic regions. Sturgeons hatch in rivers, where they feed in brackish waterways and estuaries before returning to sea at adolescence. Here they will grow to reproductive maturity over the next 12 to 16 years, before making the long journey upriver to spawn. With such a complex migratory pattern lasting years and often crossing national borders, the species is vulnerable to harm at many points in its lifecycle, and LFA must closely collaborate with a wide network of scientists, fishers, universities and administrations throughout the EU to release, monitor and protect the Born-produced stock.

The sturgeons are typically re-introduced as larvae, fingerlings or yearlings, with the bulk of restocking happening in the Oder catchment area and in the coastal waters of Mecklenburg-Vorpommern. Much re-stocking is coordinated with scientists and fishers in other EU countries as well.

Release of Baltic sturgeon fingerlings into the Oder river
© Christin Höhne, LFA

Turning the tide

From 2021 to 2023, about 553 thousand Baltic sturgeons were stocked by LFA. Around 3.3 million larvae were handed over to cooperation partners for further stocking and rearing measures. Researchers have closely monitored populations, noticing progress towards recovery. The best indicator for success is the detection of large, healthy sturgeon, and since 2021, 279 specimens have been observed in the Baltic Sea region, many over 1m in length.

The monitoring of populations is an on-going effort and will continue, along with restocking, under the EMFAF. A recent study, where 120 stocked Baltic sturgeon were fitted with acoustic transmitters, confirmed the successful migration of Baltic sturgeon from the Oder river basin to the Baltic Sea.

Gerd-Michael Arndt, the Head of the Institute of Fisheries of the LFA, explains that 'regular reports of detected sturgeon show us that the animals can survive and grow even under today's conditions. This encourages us in the hope that we can rebuild self-sustaining sturgeon stocks in the Baltic Sea in the long term.'