163 resultados para COD
Resumo:
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.
Resumo:
Assessments on NE-arctic stocks of cod, haddock, saith, redfish and Greenland halibut were carried out by the ICES 'Arctic Fisheries Working Group' in August 1996. Whereas stocks of cod, haddock, and saithe are presently in fairly good and stable condition the assessments show the stocks of beaked redfish and Greenland hailibut to be just the opposite. The status of the golden redfish stock seems to be stable. More detailed information is given in this report.
Resumo:
The German trawlfishery on cod in the German Bight causes discards. Their amount since 1983 has been estimated. The losses of millions of fish finally is the reason for losses of thousands of tonnes of valuable landings. The fishermen therefore should improve the selection rate of their nets.
Resumo:
The investigations on the fecundity of cod from different areas of the Baltic Sea started in 1992. The samples were collected in ICES Sub-divisions 25 (Bornholm Sea). 24 (Arkona Sea) and 22 (Mecklenburg and Kiel Bay). This article surnmarizes the results of 435 analysed gonads from females of age groups 1 to 8 with total length of 24 - 116 cm of the years 1992 to 1995. The gonads were prepared and analysed according to the methods which were deseribed in Bleil and Oeberst (1993). The aim of the investigations is to estimate the reproduction potential of cod for different areas and years. For this reason the absolute and relative fecundity were analysed for estimating the dependence on the total length, for age groups and the weight of females. These data were estimated for the populations Gadus morhua morhua and Gadus morhua callarias. Preliminary results have shown that the absolute fecundity (fabs) is dependent on whole weight of the females. The influence of sub-divisions (SD) and years to the fecundity are very low. Additional to this data was calculated the population fecundity for the western Baltic Sea stock (SD 22 and 24). The numbers of produced ripe eggs within the western Baltic were estimated with 4055.59 x 10(9) for 1993 and 6949.85 x 10(9) for 1994.
Resumo:
Since 1991, the aggregate biomass of fish stocks inhabiting the West Greenland shelf stagnates at the lowest level. The latest survey results of cruise no. 152 conducted by FRV 'Walther Herwig III' do not indicate any improvements in state of the stocks, although no fishing effort was recently directed towards groundfish. The cod stock showed again a record low and is presently dominated by recruits of the year classes 1991 and 1993. Both year classes are considered to be weak and the cod stock is beyond the 'minimum biologically acceptable level'. Consequently, an increase in stock abundance is not expected either in short or long term. Other ecologically or economically important fish species, American plaice, redfish, wolffish and starry skate, were also found to have minimum stock abundances. By-catch estimates of juvenile groundfish taken by the shrimp fishery, operating at traditional grounds of cod and redfish fisheries, are indispensible. Analysis of climatological data from Nuuk/West Greenland indicates that climate during the past fourty years was characterized by two decades of anomalous warm conditions, and cooling which dominates the dimate since 1969. Anomalous cold events were encountered during 1983, 1984 and during 1992, 1993. Similar to the air temperature anomalies, autumn temperatures of the ocean surface layer indicate cold and warm periods during the past thirty years. In contrast to the colder than normal atmospheric conditions during the early nineties, however, the ocean conditions indicate intermediate warming.
Resumo:
Experimental fishing trials were conducted in the Elbe Estuary using an experimental 3 m-standard beamtrawl. To avoid the by-catch of fish, a sorting grid was used. The elliptical grid was constructed of 6 mm diameter stainless steel bars with a spacing of 13 mm between the bars and housed in a cylindrical frame of 400 mm diameter. It was installed in the extension piece just in front of the codend angled at 45°, with a fish outlet at the top. A series of 10 tows of 15 minutes duration at a towing speed of 3 kn was done. The catch of the main codend was compared with the catch separated by the sorting grid. This achieved a reduction of 56 % of plaice (Pleuronectes platessa), 75 % of flounder (Platichthys flesus), 99 % of whiting (Merlangius merlangus), 94 % of cod (Gadus morhua) and 49 % of smelt (Osmerus eperlanus) with a mean loss of 43 % of shrimps (Crangon crangon). English grid trials in the Humber estuary using a flapper set or guiding funnel in front of the sorting grid device demonstrated reasonable lower escapement rates for fish and shrimps.
Resumo:
North-Sea whiting shows a much shorter shelf life in melting ice than other gadoid fishes like saithe, cod and haddock. It can be stored for a maximum of 14 days in ice before being rated as unfit for human consumption. Appropriate freshness indicators for whiting are: sensory tests, dimethylamine- and trimethylamine oxide-nitrogen, creatine content. Of most value for whiting is the determination of thc electric resistance by the fishtester VI.
Resumo:
A review of the NE Atlantic stocks of cod, haddock, saithe, redfish and Greenland halibut is given. The results are based on the assessments of the ICES "Arctic Fisheries Working Group" and the critical examination of the ICES "Advisory Committee on Fisheries Managment (ACFM)".
Resumo:
From 25 November until 8 Deeember 1994, a sea-going workshop with the above title was carried out on board RV "Walther Herwig IlI" under the umbrella of the Baltie Marine Biologists (BMlJ) and the International Council for the Exploration of the Sea (ICES). Under the co-convenorship of the first two authors of this paper, 11 seientists from 8 of the 9 countries bordering the Baltic Sea (except Sweden) actively involved in research monitoring into fish diseases/parasites participated. The main reason for holding the workshop was that, although fish disease monitoring programmes on the abundance and spatial distribution of fish diseases/parasites are being carried out by some of the countries bordering the Baltic Sea, there is still a striking lack of seientific information as compared to other seas, such as the North Sea. Moreover, since new fish disease monitoring programmes have recently been started (mainly by the new Baltic republics Latvia and Estonia, which recently became ICES-member countries) or are planned for the near future (Lithuania), BMB as weil as ICES felt the need for a interealibration and standardization of methodologies applied during fish disease/parasite surveys for the specific conditions in the Baltic Sea. Therefore, the major objectives of the workshop were -to obtain information about the disease/parasite prevalence in Baltic (Platichthys flesus) and other abundant fish species along a transect from the western (Mecklenhurg Bight) to the eastern (Gulf of Finland) Baltic Sea to be used as a baseline for future studies, -to intercalibrate methodologies applied for sampling, diagnosis of diseases/parasites, reporting and analyses of disease data, -if necessary, to recommend standard methodologies to be used for fish disease/parasite monitoring programmes under the specific conditions in the Baltic Sea. Although the data have yet not been completely analyzed, there is indication for some pronounced spatial trends regarding the prevalence of certain diseases/parasites, mainly for Iymphocystis and skin ulcerations in flounder but also for diseases and parasites of cod (Gadus morhua) which can be seen in figures 2 and 4. Recommendations for standard methodologies will later be published elsewhere.
Resumo:
Seven research vessels of ICES member countries participated, in order to investigate the strength of incoming yearclasses of commereially most important species. Germany took part in the investigations by R.V. "Walther Herwig III" from January 23 to February 24. Indices of a total of 330 stations indicate a positive development of the stocks of haddock, Norway pout and sprat whereas indices for cod, whiting, and herring remain in the mean of the last years. Water temperatures were up to 1 K above the longterm mean. Salinities were measured regionally both above and below mean values up to 1 0/00.
Resumo:
Two surveys in the German Bight revealed a relatively good recruitment for plaice and cod. However, with the current high effort and uneconomic way of fishing, most of these fish will end as discards. To protect young plaice during the winter months an increase of the mesh opening in beam trawls within the plaice box is suggested. Therefore, the fishermen are called upon to make a more considerated selection of their nets.
Resumo:
Biological investigations were carried out onboard the commercial freezing trawler "Kiel" in the Bear Island area in May/June 1995. Data will be used as German contribution to the assessments of the ICES "Artic Fisheries Working Group". Concentrations of cod were found southwest of Bear Island. Catches ammounted to 5-60 t/haul. Relatively good catches (5-25 t) with high proportions of haddock (40-80 %) were observed to the northwest of the island. Length- and age distributions as well as preliminary results of stomach- and gonad- investigations are presented.
Resumo:
In 1993 and 1994 hatching and rearing of cod eggs and larvae from the western stock was carried out aiming at data about the reproduction biology of this species. This paper describes the hatching methods and first results of the correlation between various biotic and abiotic factors, naturally fertilized eggs from a broodstock, and the amount of viable larvae.
Resumo:
Assessments on stocks of cod, haddock, saithe, redfish and Greenland halibut were carried out by the "Arctic Fisheries Working Group" in August 1995. The most important results are given in this report.
Resumo:
On 1st March 1995, the name of the former "Institut für Fangtechnik" ("Institute for Fishing Techniques") at the Federal Research Centre for Fisheries in Hamburg has been changed into "Institut für Fischereitechnik" ("Institute for Fishery Techniques"). The new conception and structure of this institute are described. Aims and possibilities of research in fishing techniques as a contribution for a selective, environment friendly and energy saving fishery are illustrated by examples in Baltic cod and eel fishery and also sea-bird bycatches, crangon fishery in the North Sea, and possible substitutions for technologies with high fuel consumption by energy saving technologies as longlining, gillnetting and anchored pound nets.