A field cage experiment to compare native and non-native fish impacts on invertebrates
Species introductions and invasions are considered as a major threat to ecosystemfunctioning due to non-native species’ potential to alter autochtone communities’ structure and function.
The round goby (Neogobius melanostomus) is an introduced fish in the Baltic Sea and is known for its high feeding rate. Adult round gobies have shown a clear preference for small bivalves and gastropods, while native species, such as the flounder (Platichthys flesus), have a wider food spectrum. The establishment of round gobies could therefore have a different effect on lower trophic levels than native fish species would have. Predation effects of juvenile round gobies remain unknown and to date, there are no experiments comparing the differential effects of round goby to native benthivorous fish on invertebrate communities in the Baltic Sea. This is an important factor to consider to be able to draw any conclusions of whether this introduced fish will have a different effect on the benthic community structure and functioning, compared to native species.
Metabarcoding procedures will be used in order to assess meiofaunal taxonomic diversity. Visual morphological taxonomic identification is usually employed to identify organisms but this traditional methodology is time consuming and do not preserve most soft-bodied meiofaunal organisms, thereby generating biased richness results. DNA-based methods will allow the identification of most meiofaunal species with high level of taxonomic resolution, with very low amount of sample biomass, and without bias associated with observer or organisms’ body size.
Non-native fish in the Baltic Sea
The round goby is an introduced fish in the Baltic Sea and is known for its high feeding rate.
Native fish in the Baltic Sea
The flounder is a native species in the Baltic Sea. They live in the same habitat as the non-native species round goby.
Aims, questions, issues
Questions we want to adress:
What is the effect of round goby predation on soft sediment benthic invertebrate?
Does the round goby have a different effect on benthic community traits than a native predator?
How to answer those questions?
The study will be conducted this summer as a field enclosure experiment at Husö Biological Station on the Åland Islands. This cage experiment will include two predator treatments (round goby vs. native species), as well as a control treatment without predators.
This project is conducted in collaboration with Heidi Herlevi who is focusing on the feeding efficiency of the round goby compared to a native species.