We are doing a collaborative research project between Stockholm University and the University of Helsinki. In this experiment we are going to investigate if the density of aquatic vegetation and drift algae and/or the vegetation traits affect(s) the composition of the macroinvertebrate community and the macroinvertebrates’ risk to be eaten by fish.

Shallow inlets are important nursery grounds for fish fry. Here, the fish fry can hide in dense vegetation, and there are often many small animals to eat. Earlier studies have shown that the risk for small animals being eaten by fish decrease if they hide in dense vegetation. But there are also studies showing that the density of vegetation does not affect the risk for small animals to be eaten. In this experiment, we are going to investigate if other factors, such as the amount of filamentous algae and plant traits, can affect the community composition of small animals that live among the vegetation, and their risk of being eaten by fish. We will be using a common method to measure predation (to be eaten), where we will set out amphipods in different densities of vegetation, and see how many survive the night. In addition, we will take a closer look at the community of fish, filamentous algae, vegetation and small animals to see what best explains the amount of eaten amphipods.

Researchers: Åsa Nilsson, DEEP, SU & Charlotte Angove, Tvarminne Benthic Ecology Team