One of the main topics of the research group is survey structure and quantification of fish population in shallow water bodies of different trophy using hydroacoustics. The aim of the bioacoustic reearch is to establish ecological rehabilitation of eutrophic waters. As a first step toward ecological restoration, the research group applies the hydroacoustics as a new technique first time in Hungary aiming at measuring the population dynamics, the structure of fish communities, size frequeny distribution, stock abundance and biomass. For characterisation of fish populations, parallel with the hydroacoustics multimesh gillnet surveys are carried out. The group applies bioacoustic technique at carrying out biomanipulation as a new management tool in restoration of shallow eutrophic water bodies. The biomanipulation is a biological manipulation using fish communities to alter the food web structure (fishery, stocking of predatory fish etc) with the aim to improve water quality of shallow ecosystems.