What will you do at Askö?

We will set up a field experiment in a shallow bay close to Askö field station, where we will exclude top predators such as perch and pike by means of cages. We will manipulate vegetation density inside the cages. Field sampling will be done regularly until the break down.

Project background

We investigate the importance of submerged vegetation for the health of shallow bays of the Baltic Sea. In the last decades, overfishing and nutrient enrichment have led to dramatic consequences for the Baltic Sea coastal ecosystem, such as strong increases of filamentous algae. Submerged vegetation may play a crucial role in buffering human impacts by 1) directly competing for nutrients with filamentous algae, 2) enhancing abundances of small crustaceans (grazers) which will feed on filamentous algae and 3) increasing abundance of predator fish such as perches and pikes, which will favour grazer survival by preying upon smaller fishes. We will test the role of vegetation under 2 stressors: 1) the addition of nutrients, and 2) the exclusion of large predator fishes by means of cage experiments with different vegetation densities.