Sind die bestehenden Regulierungsmaßnahmen für die Flunderfischerei in der südwestlichen Ostsee sinnvoll?

The reliability of the international minimum landing size of 25 cm for the flounder stock of ICES Sub-divisions 24 and 25 as well as national bans on landing female flounder during the spawning time is investigated on German samples taken in Sub-division 24. The results of the analyses of growth, sex ratio, the proportion of mature flounder, and yield curves show that 25 cm is a convenient regulation measure but it would be reliable to have an international ban on landing female as well as male flounder during spawning time.

Evaluierung der historischen Daten der deutschen Larvensurveys im Hauptlaichgebiet des Herings der westlichen Ostsee

The results of the time series of larvae surveys in the main spawning area of the western Baltic Sea spring spawning herring were evaluated. The quality of the recruitment index N 30 was studied. The raw data of 1977 to 1987 have got lost. In 1988 and 1989 the data for the estimation of the recruitment index are biased. Only since 1990 the basic data can be considered reliable.

Fischereiökonomische Forschung in Deutschland – Ergebnisse zur deutschen Fischereiflotte aus einem EU-Verbundprojekt

The economic situation of the German fishing fleet, economic indicators and backgrounds have been analysed in the overall framework of the EU-Concerted Action ‘Economic Assessment of European fishing fleets’. Trends in number of vessels, employment on board and catches for main target species are decreasing. This development may clearly be related to bad fish stock conditions, missing investment op-portunities for vessels and the short-term fishing quota man-agement system. To facilitate fisheries economics research a better data collection system is needed. As a consequence economic advice may be given for the development of a long-term sustainable management system.

Maifische an der deutschen Nordseeküste - zum Auftreten von Finte (Alosa fallax) und Alse (Alosa alosa)

Quantitative data on twaite shad are collected annually in spring and autumn since 1974 by the Demersal Young Fish Survey. Results for occurrence of these anadromous species show that twaite shad has been caught in the entire Wadden Sea area despite of the poorly suited 3-m shrimp beam trawl applied in the survey. Regional differences occur: Only sporadic catches are observed in the northern part of the German Wadden Sea, while more frequent ones occurred southwards and in the East Frisian Islands region. The obvious recent increase of abundance of Alosa fallax in spring allows for a lower ranking in the Red List of Endangered Species, while Allis shad (Alosa alosa) requires the same classification, as it was the never caught during the thirty years of surveys.

Der Anteil Transportwasser bei Heringsanlandungen mittels Vakuumsauganlage in Großraumbehältern

Estimation of the water content of herring landings caused by pressure-vacuum double tank pumps and using of multi purpose transport containers About 80 % of herring that is landed in the fish processing company Euro-Baltic Fischverarbeitungs GmbH Mukran, on the Isle of Rügen at the Baltic coast is transported from the cutter into the processing plant by pumping. For this purpose 700 l-Euro-size polyethylene tubs (containers) are filled with herring by means of a pressure-vacuum pump-systems during the unloading of the cutter. To be able to pump the fish from the hold on board it is kept floating in water (transport water). At the end of the pumping/transporting process the fish ends in a dewatering box before reaching the tub, where the transport water is separated from the fish. Then, the not completely dewatered fish is slipped into the transport containers. The amount of transport water reaching the containers depends on the type of PV-equipment and on the amount of transport water in the fish holds of the different cutters. Methodologically the mixture of fish and water must be weighed together. For the experiments specially designed transport container were used which allow the measurement of the run-off of the water to be quantified and thus to measure the proportion of water remaining with the fish. Based on 30 experiments it could be shown that on average 6 % of remaining weight of the mixture is water. Furthermore, factors were detected which influence the variability of the proportion of water.

Die Überwachungsprogramme der internationalen Meeresschutzkonventionen für Nord- und Ostsee

The international conventions for the protection of the marine environment of the North-east Atlantic Ocean including the North Sea (OSPAR) and the Baltic Sea (HELCOM) as well as the International Council for the Exploration of the Sea (ICES) have modified their structures in the recent years towards a strategy directed approach. Committees and working groups have partly changed only their names but in many cases also the scope of their subjects. In the last two years activities have been initiated to coordinate the tasks of the marine conventions and the European Union and to merge them as much as meaningful and practicable, under a common EU Marine Strategy. This article will reflect how the organisational structures have changed since the last restructuring in the first half of the nineties, and how the contaminant and bioeffect monitoring activities of the Federal Research Centre for Fisheries are implemented in these international conventions.

Entwicklung einer einfachen und schnellen Analysenmethode für Kohlenmonoxid in Fisch und Durchführung orientierender Untersuchungen

Treatment with gases containing CO, misleadingly called “tasteless smoke” or “clear smoke”, prior to freezing of fish like tuna, tilapia and swordfish (to name only a few of these species that are characterised by an intensive coloration of flesh) stabilise the fresh red colour of muscle also after thawing and suggest consumers non-existing freshness. In the European Union, carbon monoxide is excluded from being a permitted additive and therefore this handling is not allowed. Notwithstanding of the clear legal position, producers and traders are trying to establish CO treated fish on the market. In the case of taking legal measures the food control laboratories have to provide evidence that fish has been treated by CO and therefore a respective method is necessary. The method of determination of carbon monoxide in fish flesh presently applied requires considerable material and mechanistic effort to detect CO by GC after catalytic transformation into methane. The aim of our work was a direct detection of CO using suitable sensor technology. Mechanistic requirements and results of preliminary investigations to detect carbon monoxide in fish flesh will be described.

Die Fischerei im Nordostatlantik im Jahre 2004

Since 1990 North-east Atlantic fish species – arctic cod, saithe, haddock, redfish and Greenland halibut – have been investigated by on-board observers on the German commercial trawler FMS Kiel. These investigations are part of the national data collection regulation established by the European Union in recent years. Collected data are basic data for the scientific assessment of these important fish stocks of the European fisheries. The results of the observed cruises are used by the Arctic Fisheries Working Group of the International Council for the Exploration of the Seas (ICES). Biological investigations were carried out in Norwegian waters and the Barents Sea (ICES Divisions IIa and IIb) on board FMS Kiel in January to March and in August/September 2004. This report presents results of these cruises and an overview about the general fishery situation in 2004.

Die Reproduktion von Dorschen (Gadus morhua L. und Gadus morhua callarias L. ) in der Ostsee unter besonderer Berücksichtigung der Arkonasee. Teil I: Allgemeiner Verlauf des jährlichen Reifeprozesses und der Laichaktivitäten in den verschiedenen Gebieten

From 1993 to 2003 special surveys were conducted to analyse temporal and spatial aspects of the spawning activities of cod in the Baltic Sea. The ICES advice for cod in the Baltic Sea is based on yearly stock assessments of two separate stocks the western (SD 22 – 24) and the eastern stock (SD 25 – 32). Both stocks are characterized by different spawning seasons. The general progression of the maturity suggests that two types of development can be distinguished. In the western Baltic Sea (SD 22) the maturity development is temporal stable, with a relative short, main spawning period from March to April - spring spawner. In the Arkona Sea and Bornholm Basin the main spawning season starts in June and probably finishes in September - summer spawner. The proportion of spawners in summer is significantly higher than in spring in the Arkona Sea and Bornholm Basin. This again underlines the importance of the Arkona Sea for the reproduction success of the eastern Baltic cod stock. The analysis furthermore show, that the proportion of male spawners was significantly higher than the proportion of female spawners in all areas and the investigated months. This observation suggests that the reproductive success is only limited by the number of female cod which participates in the spawning process.

Die Reproduktion von Dorschen (Gadus morhua L. und Gadus morhua callarias L.) in der Ostsee unter besonderer Berücksichtigung der Arkonasee. Teil II: Statistische Analysen zum Anteil reproduktiv aktiver Dorsche in Bezug auf gebietsspezifische Unterschiede und Gemeinsamkeiten, sowie deren mögliche Ursachen.

Surveys were conducted to analyse temporal and spatial aspects of the spawning activities of cod in the Baltic Sea from 1993 to 2003. Part I of the article describes the general maturity development and the spawning activities in the western Baltic Sea, the Arkona Sea and the Bornholm Sea. The studies suggest that two types of spawner can be distinguished, the spring spawner in the western Baltic Sea and the summer spawner in the Arkona Sea and the Bornholm Basin. The descriptive analysis is supported by statistical studies presented in this article. It is shown, that the proportion of spawning individuals is significantly higher in summer than in spring in the ArkonaSea and the Bornholm Sea. Furthermore, it is shown that reproductive mixing of both types of spawner is possible in the Arkona Sea in May/June due to the hydrographical conditions in the Arkona Sea which were suitable in 8 of 10 years for successful reproduction of both Baltic cod stocks, and that spatial expansion of spawning activities of the eastern Baltic cod stock into the Arkona Sea is positive correlated with the size of spawning stock in the Bornholm Sea.

Wer fischt was? – Gemischte Bodenfischereien und ihre Auswirkungen auf die wichtigsten Nutzfischbestände in der Nordsee

Cod, haddock, whiting, saithe, plaice, sole and Norway lobster are 7 main target species of the demersal mixed fisheries in the North Sea, Skagerrak and Eastern Channel. Gadoids and Norway lobsters are mainly taken in the nor-thern North Sea by towed gears except beam trawls while the flatfish fisheries are conducted in the southern North Sea mainly using beam trawls. Recently, the central North Sea appears less fished by demersal gears. Towed nets including seines and beam trawls equipped with meshes of more than 100 mm resp. more than 80 mm were identified as the main gears effecting the depleted cod and reduced plaice stocks. The saithe sector, using towed nets with meshes of more than110 mm, longlines, gill nets and others, appears to affect the 7 species to a lesser extend. These results support the interim effort limitations by gear types, vessel and month as enforced by the European Commission since 2003. TAC regulations alone are considered inefficient to sustainably harvest stocks by mixed fisheries. A fleet-effort management method is developed estimating the fleets’ effects based on the sum of partial exploitation rates of the species in mixed fisheries weighted by the ratio of the precautionary reference Bpa and the actual SSB size as ecological quality objective. Applying such fleet effort management could result in increased catch possibilities of some stocks by fleets selecting mainly few and non-overexploited stocks while respecting precautionary management constraints in minimum SSB or maximum exploitation rates at the same time.

Wirkungsbezogene Detektion von toxischen Substanzen in Fisch und Umwelt

The detection of unknown and the quantification of known toxic substances is a challenge for the modern chemical and biological analysis. Effect-related in vitro methods, e.g. AH-receptor or estrogene-receptor mediated, offer some advantages compared to the classical chemical analysis. It could be shown that two cell lines exhibit different sensitivities to 2,3,7,8-tetrachlorodibenzodioxin (TCDD), although the cells contain the identical dioxin-receptor. The application and limitations of these methods in envi-ronmental analysis are discussed.

Entwicklung einer einfachen und schnellen Analysenmethode für Kohlenmonoxid in Fisch – Teil 2: Methodenoptimierung

After having described in our first paper (Haase et al. 2005) the main features of an easy and fast method for determination of carbon monoxide in fish and the equipment and chemicals necessary as well as first results measured on fish samples, this part deals with the influence of sample preparation, variation of the size of samples, type of solvent, duration of extraction and further conditions on the result of analyses. Both variants of the method are evaluated with regard to measuring expected errors. The single components of the equipment, including prises, are listed to allow a reliable assessment of costs. Additional instrumental colour and DSC measurements on both untreated and CO-treated tuna illustrate the effects.

27. Sitzung des FAO/WHO-Codex-Alimentarius-Komitees für Fische und Fischerzeugnisse

1963 wurde von der FAO und WHO die Codex-Alimentarius-Kommission gegründet, die Lebensmittelstandards, Richtlinien und Vorschriften wie Codes of practice im Rahmen des gemeinsamen FAO/WHO Food Standards Programme erarbeiten sollte. Hauptziel dieses Programmes ist der Schutz der Gesundheit der Verbraucher und die Sicherung fairer Praktiken im Lebensmittelhandel sowie die Koordinierung der Arbeiten zu Lebensmittelstandards, die von international, staatlichen und nicht-staatlichen Organisationen durchgeführt werden.

Ein Modell der mathematischen Optimierung zur Bestimmung der optimalen Größe und Struktur der deutschen Fischereiflotte unter stochastischen Bedingungen

A mathematical model to optimize the German fishing fleet is draftet and it’s data basis is described. The model has been developed by Brodersen, Campbell and Hanf in 1994 to 1998. It could be shown, that this model is flexible enough to be applied successfully to a lot of very different political questions, if adapted accordingly. The economic consequences of measures of fishery politics, the effects of technical advances, but also increasing incertainties can, to some degree, appropriately be assessed quantitatively. Finally it could be shown that, principally, the available account of data is a good basis for investigations into fishery economics and fishery politics. However there is a need to treat the source of data continuously and competently in order to make these informations available quickly. Statistical data to reflect the fishery sector are valuable. However, they obtain their full value only when judged by experts from the fishing industry, biology and technical fishery research.