The physical and chemical properties of the ocean control the distribution and population dynamics of fish and other marine organism to a large extent. While the large-scale distribution of marine organisms is mainly affected by latitude and ocean circulation, meso-scale processes like fronts and eddiesmay affect fish life traits and the suitability of marine habitats on the short-term. A primary goal of our research unit is to investigate such interactions at different temporal and spatial scales.
To understand and eventually predict the influence of the physical processes on fishes, we conduct long-term observational programs and develop new observational strategies and techniques. We also use various data sources (e.g. satellite data, output from global and regional circulation models) for our analyses. Currently, we make an effort to develop biophysical models, which are particularly useful to get new insights into the interrelationship between ocean physics and marine organisms.
A further aim of our unit is to expand and develop automatic, non-invasive measurement methods for marine organisms and fishes. Routinely applied ship-based hydroacoustic detection of pelagic fishes provides us with abundance and biomass indices that are an important component of ICES stock assessments. Furthermore, we collect temporally and spatially highly resolved fish distribution data that can be compared with environmental influences. A completely new approach is a coupling of both acoustic and optical methods that allows species identification and length measurements of the detected fishes. Another current subject is the application of multifrequency and multibeam echosounders that allow to expand our research to species that hitherto could not be detected, identified and quantified with hydroacoustic methods.