Chiemsee to track spread of invasive quagga mussel

A scientific monitoring programme will study the spread of the invasive quagga mussel in Chiemsee and its effects on the lake’s ecosystem, BR reported. The Upper Bavaria district authority is planning the work with Ludwig Maximilian University of Munich.

The study will examine mussel densities at different depths, chlorophyll and oxygen levels, and effects on fish stocks. The monitoring is expected to begin in early 2027, with funding from the Government of Upper Bavaria. Information boards and leaflets will also aim to alert people who take part in water sports to the risk of spreading the mussel to other lakes in Upper Bavaria.

The district committee approved the project on Thursday, according to the Upper Bavaria district authority. The monitoring is intended to show the mussel’s long-term effects on the lake’s food web and ecology.

Originally from the Black Sea region, the quagga mussel was first found in Chiemsee in 2024. It has since been detected in Starnberger See and Simssee, while genetic traces have been found in Ammersee. Its spread through European inland waters is increasing, although the exact way it travels is not fully understood. Boats and water sports equipment are considered possible ways it is transported.

The mussels filter large amounts of plankton from the water. This can make lakes clearer but removes a food source for native species, particularly young fish and the Renke, a fish that relies heavily on plankton. The mussel can also damage water pipes and boat propulsion systems.