Dreissenid mussels are rapid invaders in temperate freshwaters. Nowadays, competition between the recent newcomer, the quagga mussel (QM), and the zebra mussel (ZM), introduced earlier, can be followed in Lake Balaton, the largest shallow lake in Central Europe. Tracking the population dynamics of the two dreissenids in the past decade, we show the displacement of the ZM by the QM in the food-limited eastern basin, and their co-existence in the food-rich western basin. Chl-A, as an indicator for the mussel food algae concentration, shows a significant drop along the west-east axis of the food-rich western basin (25-4 µg/L) and is uniformly low (2-4 µg/L) in the food-limited eastern basin. Chl-A concentration correlates with carbohydrate and protein content, and with the expression of genes involved in stress response in the QM, whereas inversely relates to lipids, however, only in the western basin. In the food-rich basin, the ZM do not differ from the QM in weight, protein and carbohydrate contents, but have higher lipid content and stress gene expression. After transplantation of mussels from the food-rich to the food-limited basin, the ZM stops growing, and its macromolecular content becomes lower, whereas, despite decreased protein and carbohydrate content, the QM increases its length and lipid content. Results suggest that the QM can better adapt to food limitation than the ZM, likely due to the ability to replace missing storage carbohydrates with accumulated lipids. Change in metabolism could be an important advantage of QM over ZM in their competition.

Primary Presenter: Zoltan Serfozo, Balaton Limnological Research Institute, Eötvös Lóránd Research Network (serfozo.zoltan@blki.hu)

Authors:

Zoltan Serfozo, Balaton Limnological Research Institute, Eötvös Lóránd Research Network, Tihany, Hungary  (serfozo.zoltan@blki.hu)

Csilla Balogh, Balaton Limnological Research Institute, Eötvös Lóránd Research Network, Tihany, Hungary  (balogh.csilla@blki.hu)

Nora Farago, Biological Research Center, Institute of Genetics, Eötvös Lóránd Research Network, Tihany, Hungary  (farago.nora@gmail.com)

Jaroslaw Kobak, Nicolaus Copernicus University, Faculty of Biological and Veterinary Sciences, Department of Invertebrate Zoology and Parasitology, Torun, Poland  (jkob73@umk.pl)