20 Years of the German Small-Scale Bottom Trawl Survey (GSBTS): a Review
Senckenbergiana maritima 37 (1) 13 – 82 Frankfurt am Main 30.03.2007 20 years of the German Small-Scale Bottom Trawl Survey (GSBTS): A review Siegfried Ehrich, Sara Adlerstein, Uwe Brockmann, Jens Floeter, Stefan Garthe, Hilmar Hinz, Ingrid Kröncke, Hermann Neumann, Henning Reiss, Anne F. Sell, Manfred Stein, Vanessa Stelzenmüller, Christoph Stransky, Axel Temming, Gerd Wegner & Gerd-Peter Zauke With 50 Figures, 18 Tables, and 1 Appendix Keywords: fish assemblages, predator-prey interactions, geostatistics, benthos, seabirds, nutrients, hydrography, temporal variation, sampling method, scale, survey design, IBTS, North Sea Abstract [Ehrich. S. et al. (2007): 20 years of the German Small-Scale Bottom Trawl Survey (GSBTS): A review. – Senckenbergiana maritima, 37 (1): 13 – 82, 50 Figs., 18 Tabs., 1 App., Frankfurt a. M.] The German Small-scale Bottom Trawl Survey (GSBTS) was initiated in 1987 in order to provide com- plementary investigations to the International Bottom Trawl Survey (IBTS) in the North Sea, using the same methodology but focussing high-intensity sampling on selected survey areas. Over the last 20 years, the initial number of 4 survey areas (10 ×eschweizerbartxxx 10 sng- nautical miles; “Boxes”) has been increased to 12, which are distributed over the entire North Sea. This paper describes the survey methods of the GSBTS, summarizes the scientific outcome of the first 20 years, and suggests that international fisheries research institutions would join the GSBTS. The major outcomes of the survey include to date: – Documentation changes in the distribution of fish species and in species assemblages (e.g. changes in species richness, shifts in the southern species component). – Geostatistical evaluation of GSBTS data.
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