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The brackish lagoons around the German island of Rügen in the southern Baltic Sea are known as outstanding fishing areas, especially for large pike. However, pike catches and catch sizes have been declining for several years.  There are many reasons for this: loss of spawning grounds, decline in nutrition, increased natural mortality due to cormorants and other natural predators, climate change and overfishing.

In the vast, open ocean with no place to hide, sardines group together for protection. When they cannot rely on speed to escape, the sardines’ best chance is to outmaneuver the predator altogether. However, predators also seek ways to find weak spots in the group’s defence.

Even deep clear water lakes, which are considered particularly valuable ecosystems, can show signs of eutrophication and algae growth - often for no apparent reason. A new study by four researchers from the Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB) now shows that the causes are not always to be found in increasing nutrient inputs from the catchment area or in re-dissolution processes in the deep areas of a lake, but also in the shallower areas up to a water depth of around 20 metres.

The Stifterverband has honoured two outstanding Leibniz researchers from Berlin with the ‘Research in Responsibility’ science award. IGB researcher Robert Arlinghaus shares the 40,000-euro prize with Lena Hipp from the WZB Berlin Social Science Center.

Cigarette butts do not belong in the environment. Yet they often end up there, especially near water bodies. A survey by IGB has shown that many of Berlin's waters contain considerable amounts of nicotine, which is also toxic to aquatic life. A new IGB study now shows that some organisms may benefit indirectly: toxic cyanobacteria. This is because cigarette butts in the water harm their parasites. The study was published in the journal Ecotoxicology and Environmental Safety.

Why do animals actually hunt in groups, when they have to share the prey afterwards? Researchers have shown in a field study in the ocean off Mexico: the faster the prey school moves, the higher the capture rate of the striped marlin. This is because if the prey school is moving fast, individual prey fish are more likely to become isolated from the swarm. These isolated fish are then easily caught by the non-attacking marlins. This shows an advantage of group hunting for the predatory fish.

It is a milestone in European species conservation: Today, one hundred young European sturgeon (Acipenser sturio) were released into the Elbe River near Magdeburg as part of a long-term reintroduction programme and in the presence of the German Environment Minister Steffi Lemke. It is the first sturgeon offspring for the river since 2015. This action is an important step towards re-establishing a self-sustaining sturgeon population in one of Germany's largest river systems.

A team of scientists collected and analysed water samples at the time. The result, published in Nature Water today, showed that high concentrations of organic micropollutants exacerbated the lethal effects of prymnesin.