Duration: 01 to 21 December 2025

Area: North Sea

Purpose: Survey of benthic fish fauna in the North Sea (GASEEZ)

As part of a long-term series of expeditions, qualitative and quantitative surveys of benthic fish fauna in the German Exclusive Economic Zone (EEZ) of the North Sea have been conducted since 2004. With the exception of two outlying stations, the majority of fishing stations are distributed across the entire area of the EEZ and coastal waters. They are based on water depth and the location of eight ecological areas, which are mainly defined by benthic communities. In conjunction with the results of studies of benthic invertebrate fauna conducted by other research institutes, the aim is to identify possible changes caused by increasing industrialisation (wind farms; sand and gravel extraction).

Tasks of our research trip:

1. Fisheries biology studies. The programme focuses on monitoring demersal fish fauna in the EEZ, with particular emphasis on stock assessments of cod and whiting, as well as the flatfish species plaice and dab. The 65 fishing stations included in this year's survey are largely the same as last year. Due to the exclusion of bottom fishing in Natura 2000 areas, the "Borkum-Riffgrund" and "Sylter Außenriff" areas will no longer be fished in future. The positions of the former cod survey are also taken into account in order to maintain the time series. All stations will remain unchanged in the coming years in order to establish a long-term series. This will enable changes in fish stocks and ecology in this sea area to be assessed.
2. Hydrographic investigations. Temperature and salinity measurements are taken at individual fishing stations using a crown water sampler and a Seabird 19plus probe. These measurements are intended to provide background information on the observed distribution and behaviour patterns of the fish communities encountered.