Aluminium in Fisch und Fischereierzeugnissen

Recent reports associating aluminium with several skeletal (osteomalacia) and neurological disorders (encephalopathy and Alzheimer’s disease) in humans suggest that exposure to aluminium may pose a hazard to health. This requires the examination of aluminiumcontent in different foodstuffs. Therefore, an analytical method for the determination of aluminium in fish and fishery products, especially in fishery products packaged in aluminium cans, was developed using graphite furnace atomic absorption spectrometry. Fillets of lean and fatty fish showed aluminium levels lower than 1mg/kg wet weight, muscle of crustacean, molluscan and shellfish had apparently higher aluminium levels (up to 20 mg/kg wet weight). The aluminium content in some aluminum-canned herring was much higher than the content found in herring caught in the North Sea. These results indicate that aluminium is taken up by the herring fillets in aluminium cans, presumably through the slight and slow dissolution of aluminium from the can wall, due to some defects in the protective lacquer layer. A comparison of the aluminium levels measured in canned herring with the average aluminium-intake (normally between 3 and 5 mg/day) or with the provisional tolerable daily intake of 1mg/kg body weight per day (WHO 1989) indicated, that the aluminium content of the edible part of aquatic food does not play a significant role. High consumption of fish fillets does not pose any health risk.

Norwegens Fischerei 1996: Anlandungen und Erlöse weiter gestiegen

Norway’s sea fishery 1996 ranked 9th world wide. Preliminary data for 1996, as published in the Norwegean journal Fiskets Gang, show a further increase of the total catch by 114 000 tonnes, which now reached 2.63 million tonnes. The value of these landings were 8550 million nkr, up by 381 million nkr. The 5 most caught species were herring, cod, blue whiting and saithe. The 5 highest values, however, were obtained by cod, mackerel, herring, saithe and deepsea prawn. Considerable increases of prices were noted for jack mackerel (+142 %), mackerel (+133 %) and herring (+34 %).

Bestimmung der Begriffe Gesamtfang, Fang, Beifang und Rückwürfe

Due to the increasing environmental awareness of the public, marine environmental protection became a general interest. Since fishery is one of the strongest direct influences of man on the marine ecosystem, it became criticised, especially because of the discarding of unused fish, which is considered as a waste of the resource. In the different types of fisheries the calculation of the amounts of discards in relationship to the landings vary strongly. One of the reasons is, however, the different use of the terms 'bycatch' and 'discard'. Thus it is important to work with equal terms and definitions, so that fishermen, protectionists and ecologists talk the same language. This contribution tries to define the following terms achieving a generally acceptable terminology which is also explained by the attached diagram.

Zur Bedeutung des Größenunterschieds weiblicher und männlicher Nordseegarnelen für die kommerzielle Garnelenfischerei

Aiming at a better knowledge on the distribution and fecundity of hibernating Crangon crangon (L.), the R.V. "Solea" in January is sampling shrimps in the German Bight since 1991. A total of 3.000 shrimps (1.608 females and 1.392 males) have been investigated with regard to total length, to the width of the carapace and to spawning activity.

Deutscher Beitrag zum internationalen Makrelen(Scomber scombrus) und Stöcker- (Trachurus trachurus) Eier-Survey

Based on the results from egg and larvae surveys, mackerel and horse mackerel are thought to form three more or less distinct stocks each in the North Sea and in the waters west of the British Isles. These are firstly the southern stocks in the southern part of the English Channel, Celtic Sea and Bay of Biscay, secondly the North Sea and finally the western stocks of both species, loeated between the Shetlands and southern Norway. It is argued here that in view of the high mobility and the extended seasonal migrations of both species a c1ear separation of the stocks can hardly be maintained. In this context the results of the 1995 mackerel and horse mackerel egg survey to the southern spawning location is presented.

Biologische Verbindungen zwischen den Rotbarschbeständen Westgrönlands und der Irmingersee

Two redfish species are expected to live off western Greenland in a broad distribution area. Except for a small population of adults in the Godthab Fjord, only juvenile and adolescent specimens have been met there, tending to increase in age from the north to the south. As taxonomic identification of single specimens is difficult the distribution of species stocks cannot be clearly identified. This paper deals with spawning areas, migration and drifting routes around Greenland respectively in relation to distributional pattern of juvenile redfish off western Greenland.

Wassertemperaturen und Häufigkeiten von Mißbildungen pelagischer Fischembryonen

Malformation rates in fish embryos have been monitored for several years in the Southern North Sea. Their occurrence was interpreted to be related to pollution because malformation rates were highest in near coastal waters known to receive high pollution loads. For embryos of all species investigated synchronous trends for the fluctuation of malformation rates over the time were registered in the areas covered with intermediate prevalences at the beginning of the studies in 1984 and maxima in 1987. Thereafter malformation rates of all species decreased significantly followed by an increase in 1996. It was found that a significant negative correlation between surface water temperature and prevalences of malformed embryos of dab (Limanda limanda) and other species existed over time and space. These correlations became increasingly visible with decreasing concentrations of organochlorines in livers of dab. From these findings it is concluded that temperatures possibly predispose developing fish embryos to the impact of pollutants.

Bewertung der Farbe von frischen und tiefgefrorenen Räucherlachsseiten mittels objektiver Farbmessung

Colour measurements were performed on smoked Norwegian salmon sides using an objective method based on the CIELab-system. The influence of a freeze/thaw cycle was evaluated. Already after a short frozen storage of 8 hours a signiticant colour difference could be noticed. This was manifested by an increase in lightness as well as in redness and yellowness as result of the freeze/thaw cycle. These colour changes were observable by eyes too.

Sensorische Bewertung, Mikrobiologie und chemische Kenngrößen von eisgelagertem Wittling (Merlangius merlangus)

During the 160th research cruise of the FRV "Walther Herwig III" in the North Sea in May 1995 an ice-storage experiment with whiting was performed. Gutted whiting with and without spleen was stored in melting water-ice. Freshness and/or spoilage were monitored by measuring sensory, chemical, physical and microbiological indicators. It was found that besides the classical sensory assessment on the cooked sample and the EU-quality grading scheme, the microbiological counts were of major importance for the determination of the degree of freshness or spoilage. The cfu (colony forming units) of spoilage bacteria on the skin correlated significantly with time in ice. A very good correlation was also found for the cfu of spoilage bacteria with the sensory assessed odour of the cooked fillet sample. The measurement of the fish tissue with the Intellectron Fischtester VI and the determination of the creatine content in fillet are both suitable freshness and spoilage indicators. The pH-value measured in different body compartments and in musele homogenate and the ammonia content are only of limited value for freshness determination. Removal of kidney did not influence the shelf life.

Fettgehalte von Makrelen in Abhängigkeit von der Größe, dem Fanggebiet und der Jahreszeit

Data on the fat content in the edible part of mackerel in correlation to the length are given for nine different fishing grounds. The samples were taken in spring and summer in the North Sea, west and south of the British Isles and in the bay of Biscay.

Fischerei und fischereibiologische Untersuchungen im Nordost-Atlantik im 1. Halbjahr 1996

Biological investigations were carried out onboard the commercial freezing trawler "KIEL" off the Norwegian coast in February/March and in the Bear Island area in May 1996. Data will be used as German contribution to the assessments of the ICES "Arctie Fisheries Working Group". Informations about the fishery and the concentrations of cod, haddock, saithe and redfish in the areas between Röst-, Nordvest-, Fuglöy-Bank and Bear Island are given. Length - and age distributions as well as preliminary results of stomach- and gonad investigations are represented.

Die Herings-Polarstamm-Theorie 250 Jahre alt - und aktuelle Bezüge

250 years ago, in Hamburg a herring polar migration theory was published as part of the "Nachrichten von Island, Grönland und der Straße Davis" from the literary remains of the mayor Dr. Johann Anderson. Based on various sources and capable to answer to the herring questions of the time, this one-stock-migration theory became international hypothesis during the following tenth of years. It still is classified as remarkable because some actual ideas on herring migration were thought already 250 years ago. Abstract DE: In Hamburg wurde vor 250 Jahren eine Polarstamm-Theorie zur Heringswanderung als Teil der Nachrichten von Island, Grönland und der Strasse Davis aus dem Nachlass des Bürgermeisters Dr. Johann Anderson veröffentlicht. Aufbauend auf unterschiedliche Quellen und in der Lage, die damaligen Fragen um den Hering zu beantworten, wurde diese Ein-Stamm-Theorie zur heringswanderung über Jahrzehnte internationale Lehrmeinung. Sie wird auch heute noch als bemerkenswert eingestuft. Denn sie enthielt vor 250 Jahren schon Gedankengänge, die noch aktuell sind.

Myxobolus aeglefini in Wittlingen (Merlangius merlangus)der Nordsee und der lrischen See

In June 1994 and 1995 stations in the North, Irish, Celtic Seas and the Channel were studied for the occurrence of Myxobolus aeglefini in whiting (Merlangius merlangus). The disease was visible externally as either white nodules of a few millimeters diameter in the upper mouth cavity, gill arches and the basis of pelvic fins and in severe cases also on the lower jaws or in the cornea and sclera of the eye. It was verified morphometrically in histological sections of infected eyes by size and shape of spores. Myxobolus aeglefini was present in low prevalences at two North Sea stations and high prevalences of up to 49 % in the Irish Sea (Solway Firth) during both cruises. Whiting between 23 and 55 cm were found to be infected. Neither length-age prevalences nor condition factors and gonado, spleen, liver somatic indices differed in diseased and healthy fishes.