Processing of German fisheries data for use in stock assessment of commercially used stocks in the Baltic Sea

Project

 (c) Thünen-Institut/A. Schuetz

DCF (Data Collection Framework): Processing of national catch, sampling and trawl survey data in the Baltic Sea

Stock assessment involves fisheries data from all countries around the Baltic Sea. To ensure that the different national fisheries data can be smoothly merged into one single data set, sophisticated preliminary work from each fishery research institute is required – also from us.

Background and Objective

The Federal Republic of Germany is obliged to collect data of the German fisheries according to EU regulation 1543/2000 (Data Collection Framework, DCF). This includes the sampling of commercial fisheries, the most important recreational fisheries and collection of important fisheries-independent data series using research cruises (priority 1 surveys). In the Baltic Sea the Thünen Institute of Baltic Sea Fisheries (OF) is responsible for the collection of these data, scientific analysis and data transmission to the International Council for the Exploration of the Sea (ICES).

Approach

The Federal Office of Agriculture and Food (BLE) is the national surveillance authority and regularly provides us with logbook data and landing slips. We merge this information with results from our biological sampling from the commercial fisheries. Observers have collected catch and length composition data on board of German commercial fishing vessels; and we analyse unsorted catch samples from the commercial fisheries. In addition, we sample the catches of the marine recreational fisheries.

With these data we determine for example the total annual catch of the German commercial fisheries. We use our discard estimates to calculate the proportion of fish that has been caught but that was returned to the sea, and hence, not landed. Using our biological measurements such as age reading, we determine the number of age 1, 2, 3 and older cod landed and discarded by the fisheries. These are important input parameters for the population model used to predict changes in stock size.

In parallel, we carry out complex internationally coordinated fisheries-independent monitoring programme such as the Baltic International Trawl Survey (BITS) for demersal fish like cod and flatfishes or the Baltic International Acoustic Survey (BIAS) for herring and sprat. The surveys serve to collect fisheries-independent information on age and abundance distribution of fish covering the entire distributional area of the stocks in a standardized way.

These data are stored in a national data base. We transmit the original data, aggregated data and nationally raised data to data bases of ICES, e.g. DATRAS, InterCatch and the Regional data base FishFrame. This task requires that we continuously adapt our data and data formats to the changing requirements of the international data bases.

Preliminary Results

Please refer to the annual reports of the Baltic Fisheries Assessment Working Group (WGBFAS) at the website of ICES www.ices.dk

Thünen-Contact


Involved Thünen-Partners


Duration

Permanent task 1.2001 - 12.2018

More Information

Projekt type:
Project status: ongoing

Publications

hits: 7

  1. Krumme U, Gröhsler T (2013) Analysis of the questionaires concerning the issue of species misreporting in the mixed pelagic fisheries in the Baltic Sea (sprat-herring mix). In: Report of the Benchmark Workshop on Baltic Multispecies Assessments (WKBALT): 4-8 February 2013. Copenhagen: ICES, pp 266-276
  2. Gröhsler T (2013) Assessment input database. In: Report of the Benchmark Workshop on Pelagic Stocks (WKPELA): 4-8 February 2013. Copenhagen: ICES, pp 417-437
  3. Miethe T, Krumme U (2013) CPUE Index for German commercial tuning fleet (side trawlers), 1995-2012. In: Report of the Baltic Fisheries Assessment Working Group (WGBFAS): 10-17 April 2013; Working Document 2. Copenhagen: ICES, pp 728-734
  4. Gröhsler T, Oeberst R, Schaber M, Larson N, Kornilovs G (2013) Discrimination of western Baltic spring-spawning and central Baltic herring (Clupea harengus L.) based on growth vs. natural tag information. ICES J Mar Sci 70(6):1108-1117, doi:19.1093/icesjms/fst064
  5. Gröhsler T (2013) German herring and sprat fisheries & stock assessment data in the Baltic Sea in 2012. In: Report of the Baltic Fisheries Assessment Working Group (WGBFAS): 10-17 April 2013; Working Document 2. Copenhagen: ICES, pp 735-761
  6. Gröhsler T (2013) German herring fisheries & stock assessment data in the Western Baltic in 2012. In: Report of the Herring Assessment Working Group (HAWG) . Copenhagen: ICES, pp 806-818
  7. Krumme U, Gröhsler T (2013) Sprat (BS)/Central Baltic Herring (CBH): Analysis of the questionnaires concerning the issue of species misreportning in the mixed pelagic fisheries in the Baltic Sea (sprat-herring mix). In: Report of the Benchmark Workshop on Baltic Multispecies Assessments (WKBALT): 4-8 February 2013. Copenhagen: ICES, pp 266-276