Nils Sternberg

Research interests

I am a biologist with a great enthusiasm for limnology, especially the ecology of rivers and lakes. I am particularly interested in the coexistence of organisms in their habitats and the ecology of aquatic vertebrates. After my bachelor's degree in biology at the Ruhr University Bochum, I inevitably specialised in fish in my master's degree (M.Sc. Fish Biology, Fisheries and Aquaculture) at the Humboldt University in Berlin.

In my doctoral thesis, I am focussing on the diversity of minnows (Phoxinus spp.) in the Sieg system. Unlike historically described, in addition to the native species Phoxinus phoxinus, two different minnow species (Phoxinus csikii and Phoxinus septimaniae) can be found in the Sieg system today. These three species can interbreed and produce viable hybrids. Due to the strong mixture and the wide distribution of the three species throughout the entire Sieg system, it can be assumed that a hybrid swarm has established locally and is now spreading throughout the system. My project is therefore dedicated to the ecological and morphological aspects of the life of the three minnow species and their hybrids. Using ecological niche and dietary analyses, I will identify the ecological characteristics of the different minnow species and their hybrids. Furthermore, I will use geometric morphometrics to quantify similarities and differences in the overall body and functional head morphology of the minnows. Additionally, I am investigating the causes of the occurrence and ways of introduction of the two non-native Phoxinus species in the Sieg system. In this way, I would like to contribute to the state of knowledge about the cryptic species complex Phoxinus in Europe and the phenomenon of hybridisation in small fishes.