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.

Ostseedorschselektion - bestehende und vorgesehene neue technische Maßnahmen

Since the beginning of the nineties the situation of the Baltic cod stock is deteriorating constantly. The fishery administration (International Baltic Sea Fisheries Commission) tries to counter this by issuing new technical measures. Existing measures (raise of mesh opening from 105 to 120 mm, “Danish” and “Swedish” escape windows) and newly introduced technical measures (BACOMA codend and raise of the mesh opening in conventional codends to 130 mm) show a number of deficiencies putting their efficiency in doubt. Available well tested alternatives to the newly introduced measures without their negative side effects (codends made of netting turned by 90°, and other designs) are presently left out of regard. Models of socioeconomic effects are likewise ignored.

Fangmengenbegrenzungen in der Garnelenfischerei - eine Chance fur weitere Biefangreduzierungen

Aiming for price stabilisation Danish, German and Dutch brown shrimp fisheries agreed on weekly catch limitations for the years 1998 and 1999. This resulted in fishing effort reduction of 18 % of the total number of fishing trips in 1998 and up to 24 % in summer. In that period highest abundance of young plaice occurs in the Wadden Sea which is the fishing area of the brown shrimp fleets of Germany and the Netherlands. Consequently as a side effect a reduction of the total annual by-catch especially of young plaice must have occurred. According to formerly conducted EU-studies and investigations the by-catch reduction due to the agreed catch limitations should have led to survival of millions of young plaice. They give a potential of some extra catch in coming years which is 2,5 % of the total TAC of plaice in the North Sea. Compared to the German TAC in year 2000 the gain equals 44 %. The catch limitations effect on by-catch reduction in 1998 was in the same order of magnitude of the one achievable by technical measures in net selection applied in that fishery and research. A combination of both could substantially reduce traditional by-catch levels in brown shrimp fisheries.Aiming for price stabilisation Danish, German and Dutch brown shrimp fisheries agreed on weekly catch limitations for the years 1998 and 1999. This resulted in fishing effort reduction of 18 % of the total number of fishing trips in 1998 and up to 24 % in summer. In that period highest abundance of young plaice occurs in the Wadden Sea which is the fishing area of the brown shrimp fleets of Germany and the Netherlands. Consequently as a side effect a reduction of the total annual by-catch especially of young plaice must have occurred. According to formerly conducted EU-studies and investigations the by-catch reduction due to the agreed catch limitations should have led to survival of millions of young plaice. They give a potential of some extra catch in coming years which is 2,5 % of the total TAC of plaice in the North Sea. Compared to the German TAC in year 2000 the gain equals 44 %. The catch limitations effect on by-catch reduction in 1998 was in the same order of magnitude of the one achievable by technical measures in net selection applied in that fishery and research. A combination of both could substantially reduce traditional by-catch levels in brown shrimp fisheries.

Entwicklung des Aufwandes in der deutschen Garnelenfischerei

The German brown shrimp fishery experienced considerable changes during the recent four decades. Contrarily to the decline in number of vessels the technical standard and size of the shrimping vessels improved and the fishing power as well as the effort of the single boats have strongly increased. As fishing effort by the whole fleet may be calculated different ways, trends in total effort may differ according to the relevant author´s approach. The present study tries to estimate the total trawled area by the fleet in the mid fifties as well as in 1996. The result is that there seems to be no change in the order of magnitude of the total trawled area for the German shrimping fleet itself, though shifts in geographical areas as within seasons were reported. However, the development of the Danish and Dutch shrimping fleets have contributed to an increase in terms of annually trawled area. Therefore pooled fishing effort must have increased considerably.

Deutsche und internationale Bestandsuntersuchungen an Heringen mit hydroakustischen Methoden

The international hydroacoustic herring survey in the North Sea is carried out since the early eighties with Dutch, Scottish, Danish und Norwegian contribution. Since 1994 Germany also participates in this survey on a regular basis and has taken over a sector in the easter part between the Dogger Bank and the Danish coast. This area is known for the abundance of chiefly juvenile herring and sprat. During the 1995 cruise some 420000 t of herring were found here, most of them being juveniles of age group I. Analyses of plankton hauls showed that planktonic echos were not caused by juvenile herring, instead the echos were apparently produced by small pelagic gastropodes of the genus Spiratella.

Da genialidade sensível ao amor à norma: existência e consciência em Kierkegaard

Essa dissertação pretende deter-se sobre três pequenos e específicos textos constantes da obra Ou... Ou, do dinamarquês Sören Aybe Kierkegaard (1813-1855). Os dois primeiros textos são Os estados eróticos imediatos e Diário do Sedutor, e estão entre os textos da primeira parte do livro supracitado; o terceiro texto intitula-se O equilíbrio entre o estético e o ético na formação da personalidade e pertence à segunda parte do mesmo livro. Partindo de uma explicitação detalhada do conteúdo destes textos pretende-se pensar a questão dos estádios kierkegaardianos (estético, ético e religioso) e a forma como estes se relacionam com a existência e a consciência. No âmbito da existência concreta, a questão da consciência aparece para o filósofo dinamarquês a partir da explanação destas três dimensões existenciais, as quais se constituem em sintonia com disposições afetivas e também com modos materiais de viver e agir, detidamente descritos pela existência cotidiana de personagens. Desprovida, inicialmente, de qualquer determinação, a consciência vai se concretizando a partir de sua existência sensível, que guarda constantemente diferentes momentos ou possibilidades próprias. A tese fundamental a ser discutida, neste contexto, é a de que esses momentos existenciais não podem ser considerados de forma evolutiva, mas precisam ser tomados como possibilidades ou formas de vida, com sua positividade e seus riscos. O trabalho pretende mostrar de que forma as leituras correntes da filosofia de Kierkegaard tendem a enaltecer o aspecto ético e moral dos estádios, acabando por ignorar a dimensão mais originária do ser, qual seja, a dimensão da disposição imediata que, ao ser desprezada, abre um flanco entre o homem e ele mesmo.

Creation of temporary ponds for amphibians in northern and central Europe

More than 4000 ponds have been created or restored in Denmark since 1985 as part of a large-scale pond-digging programme to protect endangered amphibians in particular and pond flora and fauna in general. Most ponds are created on private land with public financing. The programme was triggered by, among other factors, a drastic decline in amphibian populations in Denmark between 1940 and 1980. However, in recent years there has been an increased awareness in Denmark that temporary ponds are important for the conservation of some of the most rare amphibian species, such as fire-bellied toad Bombina bombina, natterjack toad Bufo calamita and green toad Bufo viridis. Other rare species such as moor frog Rana arvalis and European tree frog Hyla arborea also benefit from temporary ponds. The last 15 years of work on the conservation of endangered species and their habitats has resulted in a last-minute rescue and a subsequent growth in the size of most Danish populations of fire-bellied toad and green toad; some populations of the relatively more common natterjack toad have also increased. The creation of temporary ponds plays an important role in the success of these three species. The creation of ponds to help restore viable populations of the most rare amphibians has not been easy. To study the conditions that may need to be created, Danish herpetologists searched for areas with temporary ponds that had good water quality, natural hydrological conditions and a management regime influenced by traditional agricultural methods. The paper gives an overview of pond creation and restoration projects in Denmark and Poland and their significance for amphibian diversity.

Reflex impairment as a measure of vitality and survival potential of Atlantic cod (Gadus morhua)

A ssur ing the v itality and survival potential of live-caught Atlantic cod (Gadus morhua) is important for improving the sorting of fish before net penning operations designed to hold fish for growth and later market. When Atlantic cod are captured by Danish seine, the most commonly used fishing gear for live-caught fish, they undergo stressors such as forced swimming, net abrasion, and air exposure. Laboratory experiments (at an air temperature of 9°C and water temperature of 8°C) were conducted with the aim of constructing a RAMP (reflex action mortality predictor) curve for prediction of vitality and survival potential in Atlantic cod captured in Danish seines, by varying the levels of these stressors. Atlantic cod exposed to increased duration in air (5–20 min) showed increased reflex impairment and mortality, with 75% mortality at 10 minutes of air exposure. Forced swimming in combination with net abrasion and air exposure did not increase reflex impairment or mortality above that associated with air exposure alone. The Atlantic cod RAMP curves indicated that fish with reflex impairment less than 50% would not show mortality and would likely recover from capture stress.

The Programme for Integrated Development of Artisanal Fisheries in West Africa

The Programme for Integrated Development of Artisanal Fisheries in West Africa (IDAF) was initiated in 1983 to help some 20 coastal states from Mauritiana to Angola which wished to develop and manage their artisanal fisheries through participatory and integrated approaches. IDAF was initially financed by Denmark and Norway. The second phase of the programme which started in January 1989 and its third phase, July 1984 are entirely financed by Denmark through the Danish International Development Assistance (DANIDA). IDAF objectives and activities to meet its goals are briefly discussed together with its beneficiaries and accomplishments.

Distribution of surface sediments off Indus delta on the continental shelf of Pakistan

Surface sediments from the continental shelf area off Indus delta were analysed for their textural characteristics and carbonate content. The sediments are largely silt, silty clay and clayey silty sand. Sandy fraction is dominant in the outer region with relatively high carbonate content. The study shows that distribution of carbonate in sediments off Indus delta continental shelf is controlled by the dilution of terrigenous material and its distance from source area.

Assessment of cattle genetic introgression into domestic yak populations using mitochondrial and microsatellite DNA markers

Hybridization between yak Poephagus grunniens and taurine Bos taurus or indicine B. indicus cattle has been widely practiced throughout the yak geographical range, and gene flow is expected to have occurred between these species. To assess the impact of cattle admixture on domestic yak, we examined 1076 domestic yak from 29 populations collected in China, Bhutan, Nepal, India, Pakistan, Kyrgyzstan, Mongolia and Russia using mitochondrial DNA and 17 autosomal microsatellite loci. A cattle diagnostic marker-based analysis reveals cattle-specific mtDNA and/or autosomal microsatellite allele introgression in 127 yak individuals from 22 populations. The mean level of cattle admixture across the populations, calculated using allelic information at 17 autosomal microsatellite loci, remains relatively low (mY(cattle) = 2.66 +/- 0.53% and Q(cattle) = 0.69 +/- 2.58%), although it varies a lot across populations as well as among individuals within population. Although the level of cattle admixture shows a clear geographical structure, with higher levels of admixture in the Qinghai-Tibetan Plateau and Mongolian and Russian regions, and lower levels in the Himalayan and Pamir Plateau region, our results indicate that the level of cattle admixture is not significantly correlated with the altitude across geographical regions as well as within geographical region. Although yak-cattle hybridization is primarily driven to produce F-1 hybrids, our results show that the subsequent gene flow between yak and cattle took place and has affected contemporary genetic make-up of domestic yak. To protect yak genetic integrity, hybridization between yak and cattle should be tightly controlled.

Effects of Prenatal Exposure to a 50-Hz Magnetic Field on One-Trial Passive Avoidance Learning in 1-Day-Old Chicks

We investigated memory impairment in newly hatched chicks following in ovo exposure to a 50-Hz magnetic field (MF) of 2 mT (60 min/day) on embryonic days 12-18. Isolated and paired chicks were used to test the effect of stress during training, and memory retention was tested at 10, 30, and 120 min, following exposure to a bitter-tasting bead (100% methylanthranilate). Results showed that memory was intact at 10 min in both isolated and paired chicks with or without MF exposure. However, while isolated chicks had good memory retention levels at 30 and 120 min, those exposed to MF did not. The results suggest a potential disruption of memory formation following in ovo exposure to MF, with this effect only evident in the more stressed, isolated chicks. Bioelectromagnetics 31:150-155, 2010. (C) 2009 Wiley-Liss. Inc.