Klassifizierung von Echogrammanzeigen

The information in the echosignal of marine scattering objects is only partially used up to now. This signal contains also informations on the biological properties of the objects. Some possibilities are described to estimate these properties from the echosignal.

Leistungsmessung an Bord von Fischereifahrzeugen zur Kontrolle der 300-PS-Begrenzung in der Schollenbox

For monitoring of the engine power of fishing vessels permitted for fishery in the plaice box with engine power of 300 HP or less at sea three different portable power measurement systems are developed and tested. A system measuring the twist of the propeller shaft by two divisible gearwheels mounted on the shaft worked well at shafts with roller bearing at both sides of the measured interval of 100–300 mm length. Only at a very few fishing vessels this system is applicable and therefore for monitoring purposes not suitable. The application of a commercial available system measuring the stress at the surface of the shaft was simplified for application by non experts. The torque is measured by strain gauges. The calibration of the system, measuring and recording of the power is done by a PC automatically. A small polished facet on the shaft protected against oxidation is needed for easy and quick application. In this case the system can be used by technical personnel of supervision boats for monitoring of the engine power at sea in a short time. A third power measurement system determinates the torque by measuring the displacement of two supports clamped on the shaft at a distance of 100 mm. The displacement is measured by a micrometer gauge mounted on one of the supports. Readout of the rotating gauge display is possible taking advantage of stroboscopic effect. The system needs no conditioning of the shaft and can be used by non technicians. The development is not finished until now and some additional investigations and tests are required. Additional measures for monitoring of the power on fishing vessels by self recording power measurement systems and sealed fuel racks with limited injection are reported and discussed.

Untersuchungen zur Sensibilität von Seefischen an Bord

First orientating investigations of the sensitiveness of the fish species dab (Limanda limanda), plaice (Pleuronectes platessa) and cod (Gadus morhua) immediately after catch and after different duration of bulk storage were carried out on board the fishing research vessel “Solea”. The aim of the investigations was to get an idea wether or not the central nervous system of the fishes was in function and the fishes could suffer pain. The proportion of sensitive dab, plaice and cod immediately after the catch was higher than 70, 80 and 95 %, respectively. After 30 min of bulk storage the percentage was reduced to 50, 60 and 70 % resp., after 90 minutes to 5, 15 % and 35 %. In cod it decreased further to 5 % after 120 min. An influence of trawling time (0,5 - 2 h) or size of the catch (100 to 1000 kg) on the number of sensitive animals was not found. Although fishing parameters in commercial fishery will in most cases put a stronger mechanical stress on the animals during trawling and handling on board a certain number of sensitive fish can still be expected.

Toxische Wirkung von Schadstoffen auf Fischzellen. Bestimmung von DNA-Strangbrüchen mit dem Comet-Assay

The alkaline comet assay is a method of detecting DNA strand breaks and alkali labile sites in individual cells. The method was used to detect DNA strand breaks in isolated blood cells (leukocytes) of carp (Cyprius carpio). DNA damage have been induced by exposure of the cells to sediment extract. Therefore comet assay can be applied as in vitro bioassay for investigations on toxicity of marine sediments.

Workshop on Customary Institutions in Indonesia: Do They Have a Role in Fisheries Coastal Area Management? Report 2-5 August 2009, Lombok, Indonesia

Sixty delegates from Indonesia, the Philippines, Thailand, Malaysia and India met at Lombok, Nusa Tenggara Barat (NTB, West Nusa Tenggara) province, Indonesia, during 2-5 August 2009, for the workshop on “Customary Institutions in Indonesia: Do They Have a Role in Fisheries and Coastal Area Management?”. The workshop was organized by the International Collective in Support of Fishworkers (ICSF), in co-operation with Indonesia’s Ministry of Marine Affairs and Fisheries (MMAF) and the Provincial Department of Fisheries and Oceans (DKP) of the Government of NTB. (PDF contains 68 pages)

Laichen von Dorschen in Gefangenschaft. Teil 1: Verlauf der Laichaktivitäten

Individuals of the western stock of Baltic cod were kept at captivity with different temperatures and salinities until natural spawning. Spawning activities up to 16 weeks were observed between February and June. This time interval agrees weIl with the spawning season of the wild cod stock. Also as in in-situ observations larger individuals started earlier with the spawning process than smaller ones and had significantly larger periods of spawning. Larger cods produced more batches and more eggs than smaller cods within this time interval. The comparison between the actual and potential absolut fecundity showed large differences. Only apart of the potential absolut fecundity, estimated in the phase of prespawning development of ovaries, was developed until their release. These analyses showed that larger cod were able to develop a larger part of the eggs within the ovaries up to the complete development. This result should be considered in the future during estimations of the population fecundity of the western Baltic spawning stock.

Oceanographic observations for the Mazatlan Project: October 1966 - August 1967

ENGLISH: To learn more about the early life of yellowfin tuna in their immediate environment, the Inter-American Tropical Tuna Commission initiated a 2-year cooperative investigation with the Direccion General de Pesca e Industrias Conexas (DGP) of Mexico in August 1966. The project called for monthly cruises of about 5 days duration to be made in a triangular track between Mazatlan, Cape San Lucas and the Tres Marias Islands. Laboratory space for the field work was provided by the DGP in their biological station in Mazatlan and the research vessel Yolanda, property of the DGP, was made available for the monthly cruises. SPANISH: Con el fin de obtener un conocimiento mas avanzado sobre la vida temprana de estos atunes aleta amarilla, y del ambiente que los rodea, 1a Comision Interamericana del Atun Tropical inicio una investigacion colaborativa de 2 anos con la Direccion General de Pesca e Industrias Conexas (DGP) de Mexico, en agosto de 1966. El proyecto requirio cruceros mensuales de unos 5 dias de duracion para que fueran realizados en un rumbo triangular entre Mazatlan, Cabo San Lucas y las Islas Tres Marias. La Direccion General de Pesca ofrecio amab1emente las facilidades del laboratorio para el trabajo experimental en la estacion biologica de Mazatlan, y e1 barco de investigacion Yolanda para los cruceros mensuales. (PDF contains 256 pages.)

Bestimmung von künstlichen Radionukliden in Konsumfisch

The identification of artificial radionuclides in fish involves some diffculties, because the quantities of these nuclides are very low (10-16 to 10-10 g/kg). The procedures have to be done very carefully. The sample preparation, the radiochemical analyses and the final preparation of the samples for the detection of the radioactivity of strontium-90, plutonium-238, -239, -240 and americium-241 are briefly described. The levels of artificial radioactivity in some species of fish from the North Sea are shown. The additional exposure to radiation by artificial radionuc1ides by ingestion of fish amounts only to about 0,02 % of the mean exposure to natural radiation. Nevertheless further monitoring of radioactivity should be continued in order to ensure that changes can be detected in time.

Erster Einsatz von Trenngittern in der kommerziellen Garnelenfischerei

Comparative fishing trials were conducted in the river Elbe estuary using 9 m commercial brown shrimp beam trawls. To avoid the bycatch of fish a metal sorting grid of the Nordmöre type was used. The elliptical grid was constructed of 6 mm stainless steel bar with a spacing of 20 mm between the bars and housed in a cylindrical frame of 800 mm diameter. It was installed in the extension piece just in front of the codend. The inclination of the grid was 45 degrees. A fish outlet was provided in the upper panel of the trawl at the upper edge of the grid. A series of 8 tows of 15 min duration at a towing speed of 3 kns was done. For evaluation the catch of the main codend was compared to the portion of the catch escaped through the grid. The presence of the grid caused a 97.4 % reduction of the catch of lump sucker, a 90.6 % reduction of the catch of sea scorpion, a 79.3 % reduction of the catch of cod, a 58.8 % reduction of the catch of armed bullhead, a 39.6 % reduction of the catch of dab, a 34.7 % reduction of the catch of flounder, a 32.3 % reduction of the catch of smelt, a 19.8 % reduction of the catch of plaice and a 14.5 % reduction of the catch of brown shrimp.

Fischartbestimmung von Caviar durch Protein- und DNA-Analyse

Deutscher Caviar, made from roe of lumpfish or capelin, gives species specific patterns in protein electrophoresis. The same techniques can be used to differentiate caviar from salmon and trout. The differentiation of sturgeon caviar (beluga, osietra, sevruga) is possible by isoelectric focusing, but not by SDS-PAGE. PCR-based methods of DNA-analysis for identification of the origin of sturgeon caviar are under development.

Einfluß von Eis- und Tiefgefrierlagerung/Auftauen auf die Länge von Seefischfilets

The objective was to study the influence of biological and processing conditions on the evaluation of a conversion factor between fillet length and fish size. This paper presents changes of the length and weight of skinless fillets from various marine fish species in relation to the ice storage time and to the deep freezing / thawing process. The biochemical changes during rigor mortis lead to considerable reduction in length of skinless fillets during ice storage and deep freezing / thawing of fillet blocks. The investigations were undertaken during various cruises of the FFS „Walther Herwig III“.

2. Weltfischerei-Kongreß

Vom 28. Juli bis 1. August 1996 fand in Brisbane/Australien der 2. Weltfischerei-Kongreß statt. Er stand unter dem Motto „Entwicklung und Erhaltung der Weltfischereiressourcen - Stand von Wisssenschaft und Management“. Gastgeber war die Australische Gesellschaft für Fischereibiologie, Hauptsponsor die Australische Fischereiforschungs- und Entwicklungs-Vereinigung.

Dokumentation eines Einstroms von warmem salzhaltigem Wasser in das Bornholmbecken im Oktober 1996

The Institute for Baltic Fisheries, Rostock, performed three research cruises with different aims in autumn (September - November) 1996. The area of investigation ranged from the southern Kattegat, the Belts, the Arkona Sea to the Bornholm Basin. With a CTD memory probe hydrographical data were sampled after many trawl stations from the surface to the bottom. These data document a saltwater inflow in the deeper water of the Bornholm Basin at the beginning of November.

Vergleich von Ausbeutefaktoren und Eislagerqualität zwischen Kliesche (Limanda limanda) und Scholle (Pleuronectes platessa) aus der Nordsee

North Sea plaice (Pleuronectes platessa) and dab (Limanda limanda) were experimentally stored in ice for 6 days during the 181th cruise of the FRV “Wather Herwig III”. It could be demonstrated that both flat fish species showed the same storage properties and were of a comparable quality until the end of the storage experiment. The quality of both species was determined by sensory assessment of the quality grade, by measuring of the impedance using the German Fischtester VI and the Icelandic RT- tester and pH- and TVB- N- measurements. The average length of North Sea dab is generally small (female: 18,5 ± 3,9 cm; male: 17 ± 2,9 cm), therefore it seemed to be more efficient to process fish portions (eviscerated, head, tail, fins and part of belly flaps removed). The yield by manually processed filets or fish portions from dab is about 30 or 62 %, respectively