Nationales Fischereidatenerhebungsprogramm: Aktivitäten und Ausblick

Within the frame of the EU Data Collection Regulation (DCR), Germany is obliged since 2002 to collect basic fisheries data to support the Common Fisheries Policy. Various governmental institutions are involved in the collection of landings and effort data, biological and economic data of the German fisheries. About 200 trips on commercial fishery vessels were sampled from 2002 to 2006. Additional stock data are collected on research surveys. The landings of cod in the recreational fisheries in the North and Baltic Seas were recorded within a pilot study. In order to assess the economic situation of the fishing fleet and processing industry, economic data were collected. The collected data are being stored in a national database and being made available for scientific working groups. At present, the legal regulations within the DCR framework are being reviewed and adapted to the changing requirements of fisheries management.

Entwicklung eines selektierenden Aalschleppnetzes

In eel catches with special small-mesh trawls the proportion of by-catch is unjustifiably high. From 2003 to 2005 eel trawls with various types of separation panels were designed, constructed, and tested under real fishing conditions. Tests were carried out using cover cod-ends and an underwater TV equipment. It was possible to reduce the amount of by-catch to one tenth of its usual amount. However, a decline of the catch efficiency for the target species eel could not be avoided.

The BACOMA cod-end. History and recent developments in BACOMA cod-end regulations and a proposal for abetter specification of the BACOMA cod-end for Baltic Sea cod fishery

To improve the cod stocks in the Baltic Sea, a number of regulations have recently been established by the International Baltic Sea Fisheries Commission (IBSFC) and the European Commission. According to these, fishermen are obliged to use nets with escape windows (BACOMA nets) with a mesh size of the escape window of 120 mm until end of September 2003. These nets however, retain only fish much larger than the legal minimum landing size would al-low. Due to the present stock structure only few of such large fish are however existent. As a consequence fishermen use a legal alternative net. This is a conventional trawl with a cod-end of 130 mm diamond-shaped meshes (IBSFC-rules of 1st April 2002), to be increased to 140 mm on 1st September 2003, according to the mentioned IBSFC-rule. Due legal alterations of the net by the fishermen (e.g. use of extra stiff net material) these nets have acquired extremely low selective properties, i. e. they catch very small fish and produce great amounts of discards. Due to the increase of the minimum landing size from 35 to 38 cm for cod in the Baltic, the amount of discards has even increased since the beginning of 2003. Experiments have now been carried out with the BACOMAnet on German and Swedish commercial and research vessels since arguments were brought forward that the BACOMA net was not yet sufficiently tested on commercial vessels. The results of all experiments conducted so far, are compiled and evaluated here. As a result of the Swedish, Danish and German initiative and research the European Commission reacted upon this in June 2003 and rejected the increase of the diamond-meshed non-BACOMA net from 130 mm to 140mm in September 2003. To protect the cod stocks in the Baltic Sea more effectively the use of traditional diamond meshed cod-ends with-out escape window are prohibited in community waters without derogation, becoming effective 1st of September 2003. To enable more effective and simplified control of the bottom trawl fishery in the Baltic Sea the principle of a ”One-Net-Rule“ is enforced. This is going to be the BACOMA net, with the meshes of the escape window being 110 mm for the time being. The description of the BACOMA net as given in the IBSFC-rules no.10 (revision of the 28th session, Berlin 2002) concentrates on the cod-end and the escape window but only to a less extent on the design and mesh-composition of the remaining parts of the net, such as belly and funnel and many details. Thus, the present description is not complete and leaves, according to fishermen, ample opportunity for manipulation. An initiative has been started in Germany with joint effort from scientists and the fishery to better describe the entire net and to produce a proposal for a more comprehensive description, leaving less space for manipulation. A proposal in this direction is given here and shall be seen as a starting point for a discussion and development towards an internationally uniform net, which is agreed amongst the fishery, scientists and politicians. The Baltic Sea fishery is invited to comment on this proposal, and recommendations for further improvement and specifications are welcomed. Once the design is agreed by the Baltic Fishermen Association, it shall be proposed to the IBSFC and European Commission via the Baltic Fishermen Association.

Sind südliche Arten in Nord- und Ostsee auf dem Vormarsch?

The long and warm summer 2003 resulted in water temperatures of about 2°C above the average. This promoted the immigration of southern species like the Anchovy, the Sardine, the Red Mullet and different Squid species. The possible conclusions of such invasions concerning the ordinary species of the area are rather contradictory: For the Western Baltic a positive correlation between the occurrence of Anchovy and a good Cod year-class is shown. For the southern North Sea, stomach investigations of Squid make a negative effect on fish eggs and larvae more likely.

Eu-Projekt zur Seebeprobung von Schleppnetzfangen in der Nordsee erfolgreich abgeschlossen

Six countries around the North Sea have contributed to an EU-funded project collecting information about the catch composition in commercial fisheries. The aim was, by including that part of the catch, which is discarded after sorting, to gain better knowledge about the real stock size of the most important fish species. Additionally, the data shall contribute to a better understanding of the ecological effects of trawling.

Technische Empfehlungen für den künftigen Einsatz von Plattfischsteerten in der Ostsee

Die Grundschleppnetzfischerei in der Ostsee konzentriert sich im wesentlichen auf den Fang von Dorsch- und Plattfisch. Neben der Dorschfischerei gibt es auch beim Fang von Plattfisch gebiets- und zeitweise erhebliche Beifänge an untermaßigen Fischen, die verworfen werden müssen. Für beide in Form und Verhalten sehr unterschiedlichen Fischarten können bis dato die gleichen Steerte eingesetzt werden. Um die durch diese Mix-Fischerei an der südlichen Ostseeküste gegebenen Probleme zu verdeutlichen und auf eine zukünftig differenzierte Behandlung für die technischen Maßnahmen zur Verbesserung der Selektivität hinzuwirken, werden seit 1998 vergleichende Untersuchungen mit Schleppnetzsteerten unterschiedlicher Konstruktion durchgeführt.

Kritische Betrachtung der Begriffe Fischereiaufwand und Fangkraft mit dem Ansatz einer Neubewertung

In order to restore the balance between available fish res-sources and catch capacities in the marine waters of the EU, the European Commission has introduced so-called Multiannual Guidance Programmes (MAGPs) within the frame work of the Common Fisheries Policy (CFP). However, the non-quantified relation between fishing effort and fishing power of a vessel has proved to be one of the most difficult problems. The present contribution suggests to substitute traditional but non-quantifying methods by including the real catch results into the models.

Neue Chance für den Nordsee-Kabeljau

Während der 483. Reise von FFK “Solea“ (24.10. bis 9.11.01) wurde wie in jedem Herbst die Nachwuchssituation von Kabeljau in der Deutschen Bucht untersucht. Der dabei berechnete Index hat sich in seiner 20-jährigen Laufzeit als relativ verlässliches Maß für die Abschätzung der Stärke des jeweils jüngsten Jahrgangs erwiesen.

Selektionsuntersuchungen an Schleppnetzsteerten für den Plattfischfang in der Ostsee

The intensified trawl fishery for flounder and otherflatfishes along the German Baltic coast during summer months resulted in the problem of increased undersized bycatches and their discarding. Thereforeselectivity trials with a standard codend, a codend withenlarged meshes and a so-called multipanel codendwith partly transverse netting were investigated. Results show that improvements in selectivity are possible, and tests including UW-TV observations shouldbe continued.

Die Bruttoraumzahl als neue Einheit der Schiffsvermessung

The definition of the newly introduced dimensionless parameter for tonnage measurement (German: Bruttoraumzahl (BRZ) (English: Gross tonnage (GT)) instead of Gross register ton (GRT) (German: Bruttoregistertonne (BRT) doesn’t seem to be so clear, neither for specialists. The present article gives some explanations about the history of measurement of ships and the relation between BRT and BRZ, especially for fishing vessels.

Flexibles Gitter für die Größenselektion von Ostseehering

In the Institute for Fishery Technology in Hamburg a new sorting grid for herring trawl fishery was developed which is more adapted to the commercial fishery than existing constructions. Therefore a flexible design was choosen with braided snoods as grid elements and rubber rings for shape stabilization. First tests were carried out with twin trawlers in the Western Baltic in February 1999. They proved principally the serviceability of this grid construction under commercial fishing conditions. The percentage of small sized herring was essentially reduced. Due to only few hauls more detailed quantitative statements are not possible yet.

Deutsche und internationale Dorschfischerei in der Ostsee im Jahr 1998

In 1998 the longtime series of the standardized bottom trawl surveys conducted in the western Baltic (ICES Sub-division (SD) 22 and 24 since 1978) during spring and autumn and also in the eastern Baltic (ICES Sub-division since 1993) during spring were continued. The results of the surveys as well as those of a sampling programme carried out on board of commercial cutters (mainly financed by an EU study project) and on the market, the investigation of the survival rate of the discards, and the landing statistics are the basis of the analysis of the German and international cod fishery in 1998. The German cod fishery was concentrated on the ICES SD 22 and 24 (total landings 9722 t). The total landings from the fishing grounds east off Bornholm, the traditional German fishing ground, amounted only to about 1270 t. The German cod quota was utilized at 64 %. The fishery in the ICES SD 22 and 24 was characterized by a discard rate of undersized cod of 13 %. That corresponds to about 7.3 million specimens of 0-group, one- and two-years-old youngfish, respectively. The total international cod landings of the Baltic amounted to 101 500 t. In comparison with 1997 (total landings 129 600 t) the landing decreased by 23 %. The percentage utilization of the cod TAC (1998: 140 000 t) amounted to 74 % in 1998.

Discards in der deutsche Seelachsfischerei

The saithe fishery in the Northern North Sea includes unused by-catches, that usually represent 6.1 % of the total catch. Although this relates clearly to single to species and year classes this fishery is comparatively “clean”. If such catches were better used, i.e. if the marketable fish of legal length were also landed, one could certify that the saithe fishery could be carried out without ecological concern.

Qualitat under Verwertung von Fruhjahrshering aus der Ostsee

The utilization of spring herring caught off the eastern German Baltic Sea coast in the waters around Rügen Island has a long tradition. Since 1991 there was a dramatic decrease in herring fisheries in this area. To promote the better use of this typical spring herring stock an exploratory fishery was started from January to May 1999 accompanied by quality investigations. The results show the possibilities of utilization according to length distribution, fat content and quality aspects.

Vierwöchige Gebietsschließung in der Deutschen Bucht - Eine Maßnahme zum Schutz des starken 1996er Kabeljaujahrgangs

End of January 1998 a real-time closed area has been established by the Federal Republic of Germany. As a case of emergency an area of 12 x 25 nm has been closed for trawling, to protect the mostly undersized 1996 cod year-class. The background and the valuation of this action is described.